Here are some good places to start.
Paper Money
The best place I know of to find out about paper money is the rec.collecting.paper-money
newsgroup on Usenet. To access Usenet, you will need a news reader program.
While Netscape and Internet Explorer provide rudimentary news reading facilities,
the best news reader I know if is Agent (or Free Agent) from Forte. (http://www.forteinc.com).
The folks on rec.collecting.paper-money can help you with evaluating your
collection.
Error Coins
I'm often asked about 2 headed coins. These coins are not products
of the U.S. Mint. They are produced (apparently in some quantity) by companies
selling supplies to magicians. Coin collectors will pay a couple of bucks
for one of these, but they are not collected heavily. A magician might
pay more, I don't know.
Off center coins are usually worth a couple of bucks. More if the date is still readable, and more if it is very far off center.
If you have an interest in error coins that goes beyond a single coin, then consider joining CONECA. A reasonable way to contact CONECA is to send e-mail to Steve Carr:Scarr4002@aol.com. Steve wishes it to be known that he may not be able to answer questions immediately as he doesn't read his e-mail every day. He also doesn't have the time currently to answer questions about individual coins. The president of CONECA is Mike Ellis. His address is :coneca@surfsouth.com.
You may also find information at the CONECA home page at: http://hermes.csd.net/~coneca. At this red hot moment, there isn't much information there, however there is contact information on how to join, etc. They may improve the page in the future (hint, hint).
Foreign Coins
The coins@uni.edu mailing list is a great place to get information
about foreign coins. Just remember that you can't post "for sale" postings
to this list. Information on how to join or post to the list is available
on the numismatic e-mail lists page.
A lot of common foreign coins are sold by the pound or for less than 5c a piece in junk boxes. If you know much about these coins there are a lot of nice coins out there waiting to be cherry picked.
Tokens
Tokens are coin-like items. Again, your best bet is one of the mailing
lists or newsgroups.
Coin Books
The BiblioNumis-L mailing list is the best place to go to get rare
coin books evaluated. See the numismatic e-mail
lists page.
Odd Questions
If your question is really outrageous (but still about coins) and you
can't get the answer any other way, try Alan Herbert. He is so knowledgeable
in the hobby that he is called the "answer man". His e-mail address is:
Answerman2@aol.com.




