I am an American citizen who is going to marry an Ecuadorian woman.
She came here legally with a tourist visa but it has expired over 3
years ago. We are going to marry in New York. What specific forms do
we have file with INS so she may remain and work here legally? Is it worth it
to get a lawyer or can we do the forms ourselves?

Hi  trot19,

The key to your situation is the fact that your future bride was
admitted legally into the United States and is just "out-of-status"
now (this is better than if she had crossed the border illegally). 
Given that fact, it is possible to make the petition yourselves, but
seeking the advice of an immigration lawyer is not a bad idea to make
sure all the details of your particular situation has been taken into
account, for example, whether or not your bride has been working
illegally.  That said, here is what you will need to do to adjust her
status to Permanent Resident.

1) Get married in the U.S. 
2) File Forms I-130 and I-485 with the BCIS (they can be filed
concurrently). Once these forms are filed, she will no longer be
subject to deportation.
3) Under NO circumstances (even if given permission) let her leave the
U.S. until her Permanent Residence status has been approved. If she
leaves the U.S., she will run the very real risk that she will be
considered as having abandoned her PR application and will be banned
from re-entering the U.S. for ten years.
4) If she has been working illegally, do not lie on the I-130 Form (it
gets forwarded to the IRS). It will not hurt her chances of adjustment
of status, it just means that she will have to pay back taxes.
5) The immigration authorities will require evidence that the marriage
is not a "sham" (entered into solely with the intent to obtain PR
status).

FILE A PETITION FOR ALIEN RELATIVE

"You must first file an immigrant Petition for Alien Relative, form
I-130 for your spouse with the BCIS Office that serves the area where
you live. The BCIS will send you a Notice of Action (Form I-797)
receipt notice. This notice tells you that the BCIS has received the
petition."
http://travel.state.gov/visa/immigrants_types_marriage2.html#3c

FORM I-130, Petition for Alien Relative 
http://uscis.gov/graphics/formsfee/forms/i-130.htm

REGISTER FOR PERMANENT RESIDENCY

Immediate Relatives
If you are the immediate relative (spouse, parent or unmarried child
under 21 years old) of a U.S. citizen, submit the following forms:
    * I-485, Application to Register Permanent Residence or to Adjust Status
    * G-325A, Biographic Information
    * Either your original I-130, Petition for Alien Relative (if you
are filing concurrently)
    * I-864, Affidavit of Support
    * I-693, Medical Examination of Aliens Seeking Adjustment of Status
    * All required supporting documentation as listed on the above forms. 
http://uscis.gov/graphics/formsfee/forms/i-485.htm

FORM I-485; FORM I-864; FORM I-693; package:
http://uscis.gov/graphics/formsfee/forms/files/i-485pk1.pdf

Application Procedures:
Becoming a Permanent Resident While in the United States
http://uscis.gov/graphics/howdoi/LPRApplication.htm

FILLING CONCURRENTLY

Special Instruction:
"The I-485 in this case may be filed at the same time as the visa
petition (I-130) which is filed by the U.S. citizen or lawful
permanent resident. See your local office "About Us" page for any
special local instructions including any local forms needed to apply
for permanent residence."
http://uscis.gov/graphics/formsfee/forms/i-485.htm

Petition for Alien Relative
"NOTE: If the I-130 petition is being filed concurrently with Form
I-485, Application to Register Permanent Residence or to Adjust
Status, submit both forms at the local INS office having jurisdiction
over the place where the I-485 applicant
resides. Applicants who reside in the jurisdiction of the Baltimore,
MD, District Office should submit the I-130 petition
and the Form I-485 concurrently to the USINS Vermont Service Center,
75 Lower Welden Street, St. Albans, VT 05479-0001.
If you live in Alabama, Arkansas, Florida, Georgia, Kentucky,
Louisiana, Mississippi, New Mexico, North Carolina,
Oklahoma, South Carolina, Tennessee or Texas, mail this petition to:
USINS Texas Service Center, P.O. Box 850919, Mesquite,TX 75185-0919.
If you live in Arizona, California, Guam, Hawaii or Nevada, mail this
petition to: USINS California Service Center, P.O. Box 10130, Laguna
Niguel, CA 92607-0130.
If you live in Alaska, Colorado, Idaho, Illinois, Indiana, Iowa,
Kansas, Michigan, Minnesota, Missouri, Montana, Nebraska, North
Dakota, Ohio, Oregon, South Dakota, Utah, Washington, Wisconsin or
Wyoming, mail this petition to: USINS Nebraska Service Center, P.O.
Box 87130, Lincoln, NE 68501-7130.
http://uscis.gov/graphics/formsfee/forms/files/i-130.pdf

>>>  TIMELINES

Processing Times:
https://egov.immigration.gov/cris/jsps/ptimes.jsp;jsessionid=eqO8DUrVCaS6

I hope I've been able to help you sort through the immigration maze.
If you have any questions, please post a clarification request
*before* closing/rating my answer and I'll be happy to reply.

Thank you,
hummer

I searched the USCIS website and used my own research on this subject.

First, congratulations on your engagement. 
   
    My advice to you is to not hire an attorney. The process is fairly
simple to understand. It's typical government red tape; standing in
line, filling out forms, dealing with incompetence, etc. An attorney
might save you a headache, but otherwise they are basically just going
to fill out forms for you. If you go to www.uscis.gov, you should find
all of the information you need. If you don't already have notarized
copies of personal documents, I would start obtaining those now unless
you're willing to part with the originals. Don't forget to get
certified translations of any foreign language documents, such as your
fiance's birth certificate. If you go to www.translatorsbase.com, you
can find someone to translate documents at a very reasonable cost. I
would also advise that you read the USCIS website carefully. There
have been changes made to some requirements that have not been noted
on the printable instructions for certain forms (increased fees, photo
guidelines, etc.).
    If you're semi-intelligent, you should be able to complete the
process without professional help. There's no negotiation involved,
and the waiting periods will be the same. Just be sure to read
eveything carefully and follow the instructions.
   One final caveat: Beware the fingerprinting/biometrics
"appointment"! They are not giving you a real appointment. You will
arrive at the Service Center to find 100 other people in line with the
same "appointment" time. GET THERE EARLY!

Good luck my friend.