How can I find an obituary for someone if I only have a last name and
a general location. I want to know if a gentleman withn the last name
of Avelar died on November 26, 2004 in southern California in or near
Riverside.

Although it may take some researching, often local librays have and
indexed obits, cataloged by last name.  Information can also be found
at local health departments and in Newspaper Obits.

"257 records were found" when searching for "avelar" in

"Social Security Death Index" as available on
http://www.newenglandancestors.org/research/database/ss/default.asp

"Data is current through Nov. 2004".

Only 1 record for November 2004:

"Lupe R AVELAR" "5 Nov 2004".

http://nationalobituaryarchive.com/Obituary/ -- this is an excellent
resource; unfortunately, it provided no details that were pertinent to
your quest at this time.  Keep the resource though and/or try it again
later; sometimes, it takes a little while for the obituary to be
registered on the site.  Funeral homes are working to update this
site; however, it isn't perfect.

Good luck!!