what would be the consequences of marrying my girlfriend from colombia
 when she entered the us legally with a tourist visa and I am a legal
permanent resident, what would be the best way to do this, and the
correct sequence of events, should we marry in colombia and then come
to the USA  and apply to change her status, or should we marry here and
then apply to change her status. we dont want to her to wait in
colombia and I dont want to be without her, thanks

Technically you aren't allowed to do that but once she is in the
country and you are married you simpy apply for adjustment of status
(green card) for her based on the fact she is your wife.  The bad news
is that she cannot leave the country without an advanced parole while
she is awaiting a permanent visa or she needs to wait outside the
country.

If you get married outside the country then she must wait until she
gets the visa before she can enter.

There is another alternative and that is a fiance visa.  You apply
while she is outside the country, the consulate does an interview and
then she is granted a 3 month visa and you must get married within 3
months.  Then you apply for the status adjustment.

That sounds definitive and pretty much what I recall from various
earlier references to the site of the US Citizenship and Immigration
Service:

http://uscis.gov/graphics/

You might want to check before making a decision.

The situation is a lot more complicated than the two prior commentors state. 

Please do not marry your fiance without doing some research - if you
do not do research you may be risking her legal status in the US.  The
second you are married she is without status and her Tourist Visa
becomes invalid which could have her deported.

Check this website: http://visajourney.com/ for more detailed
information.  That site will show you the options available to you,
explain them, walk you through the process, and allow you to talk with
others in the same situation.

1.  She CANNOT apply for adjustment of status - or an immigrant visa -
as the spuose of a permanent resident, unless you first file a
petition to  classify her as your spouse, and her priority date
becomes current.  The priority date is the date you file the visa
petition.  Right now only folks who applied prior to November 1, 2001
can file for permanent resident status.
2.   If you had married her before you got your status, she would have
the same priority date and same status you did.
3.  The situation changes if you become a US citizen - no priority date - no wait.
4.  Filing the petition for her does not allow her to stay in the US
or work in the US.  So she'll have to have and maintain another valid
satus if you want to remain together while this goes on for the next
many years.

J

Hopefully I have not misunderstood your points jayatlga-ga but here is
some clarification for the original poster so there is no confusion.

3.  The situation changes if you become a US citizen - no priority date - no wait.
-
Even if one individual in the couple is a US Citizen the process can
still last over 6 months.  In my case my husband is the US Citizen and
I am a Canadian Citizen - we went through the K1 process.  We applied
09-24-02 and I recieved my K1 Visa on 05-15-03.  I was able to work in
August when my AOS became effective which was the same time my EAD was
effective.

Whereas a friend of ours, a US Citizen, married his Canadian spouse in
Canada then went through the K3 process of immigrating a foreign
spouse.  They started their process spring of 2002 and the wife was
finally allowed in the US in late 2003.  And once allowed in she
wasn't able to work for well over 6 months as her Employment
Authorization Document, Adjustment of Status, and Early Patrol
documents were processed.

K1 is a Fiance(e) visa and K3 is a spouse visa - the K1 is generally
faster to process than the K3.

4.  Filing the petition for her does not allow her to stay in the US
or work in the US.  So she'll have to have and maintain another valid
satus if you want to remain together while this goes on for the next
many years.
-
Depending on what the poster decides to do: marry first then petition
(K3), or petition then marry (K1), with regards to the latter
situation the foreign individual (wife in this case) will experience a
brief period of being "without status" between the marriage (which
must happen within 90 days of entering the US on the K-1 Visa) and the
actual effective date of the Adjustment of Status - for me that "out
of status" period was approximately 60 days.