My wife and I put on charity events for various organizations.  A
problem we have had is that promotional material, such as slogans and
artwork, are reused by other groups or by the charity organizations we
are hosting the events for.  We would like to keep these things as our
own, so they can be used over and over again no matter who we decide
to donate the proceeds to.  Since we are not a business or a
non-profit organization, just a couple trying to raise money for
various local organizations, how do we protect our intellectual
property?  I am mainly concerned with our event slogans and logos.

What you are seeking is a trademark or service mark.

"A trademark is a word, phrase, symbol or design, or a combination of
words, phrases, symbols or designs, that identifies and distinguishes
the source of the goods of one party from those of others.

A service mark is the same as a trademark, except that it identifies
and distinguishes the source of a service rather than a product.
Throughout this booklet, the terms "trademark" and "mark" refer to
both trademarks and service marks."

http://www.uspto.gov/web/offices/tac/doc/basic/trade_defin.htm
"Trademark, Copyright or Patent?"  Basic Facts About Trademarks,
United States Patent and Trademark Office

"What Is a Trademark or Servicemark?
A trademark is a word, name, symbol or device which is used in trade
with goods to indicate the source of the goods and to distinguish them
from the goods of others. A servicemark is the same as a trademark
except that it identifies and distinguishes the source of a service
rather than a product. The terms "trademark" and "mark" are commonly
used to refer to both trademarks and servicemarks.

Trademark rights may be used to prevent others from using a
confusingly similar mark, but not to prevent others from making the
same goods or from selling the same goods or services under a clearly
different mark. Trademarks which are used in interstate or foreign
commerce may be registered with the Patent and Trademark Office. The
registration procedure for trademarks and general information
concerning trademarks is described in a separate pamphlet entitled
"Basic Facts about Trademarks"."

http://www.uspto.gov/web/offices/pac/doc/general/whatis.htm "What Are
Patents, Trademarks, Service Marks, and Copyrights?"  United States
Patent and Trademark Office

"Is registration of my mark required? 

No. You can establish rights in a mark based on legitimate use of the
mark. However, owning a federal trademark registration on the
Principal Register provides several advantages, e.g.,
constructive notice to the public of the registrant's claim of
ownership of the mark;
a legal presumption of the registrant's ownership of the mark and the
registrant's exclusive right to use the mark nationwide on or in
connection with the goods and/or services listed in the registration;
the ability to bring an action concerning the mark in federal court; 
the use of the U.S registration as a basis to obtain registration in
foreign countries; and
the ability to file the U.S. registration with the U.S. Customs
Service to prevent importation of infringing foreign goods.

When can I use the trademark symbols TM, SM and ®?

Any time you claim rights in a mark, you may use the "TM" (trademark)
or "SM" (service mark) designation to alert the public to your claim,
regardless of whether you have filed an application with the USPTO.
However, you may use the federal registration symbol "®" only after
the USPTO actually registers a mark, and not while an application is
pending. Also, you may use the registration symbol with the mark only
on or in connection with the goods and/or services listed in the
federal trademark registration."

http://www.uspto.gov/web/offices/tac/doc/basic/register.htm "Should I
Register My Mark?"  Basic Facts About Trademarks, United States Patent
and Trademark Office

You do not have to use an attorney to file for a trademark, but you
must comply with all rules for the filing process.  An
intellectual-property attorney is the type of attorney you would be
seeking if you decided to use one. Comprehensive information about the
filing process is available at:

http://www.uspto.gov/web/offices/tac/doc/basic/index.html "Basic Facts
About Trademarks" United States Patent and Trademark Office

Also, a toll-free number is available for more information:

"If you need answers to specific trademark questions or want to know
more about trademarks in general, please contact the Trademark
Assistance Center at 1-800-786-9199. If you live in Northern Virginia,
the number is (703) 308-9000."

http://www.uspto.gov/web/offices/tac/tmfaq.htm#Basic005 "Frequently
Asked Questions about Trademarks" United States Patent and Trademark
Office

The Trademarks homepage at the United States Patent and Trademark
Office is available at:

http://www.uspto.gov/main/trademarks.htm "Trademarks" United States
Patent and Trademark Office

I hope you find the above information and links useful.  Please
request clarification if needed.

Sincerely,

Wonko

Thank-you for your answer.  You have given me a lot of valuable places
to being my research.