Do any web search engines (you know....Google, AltaVista, HotBot, and
all the rest) treat special characters like regular letters?  That is,
can I search on $59, or *69, or @yahoo, and have the search recognize
the non-alphabetical character for what it is, and include it in the
search results?  In other words, I wouldn't want results that just
have the number 59 or 69, or the word yahoo.  Instead, I want only
results that include the special character.

As far as I can tell - none of the major search engines support what you
have described. There may be a search engine that you could install (and
search your own data) that would support it, but most engines I looked at
strip all punctuation prior to indexing.
 --Maniac

I had little success when wanting to search for $59
I search for 
" $59.00 "
" man@yahoo.com "

and some similar strategies but not really answer your question
but not really what you want.

I used to have a prolog webcrawl and which could search for e-mails
etc based
on regular expressions. was a homework assignment very slow and not
very useful but could be improved