Ok..... You know how on BBS's or tagboards you can type :) or :( or :P and it turns into a smilie??? ( I think it just did!!!!) How can I do that on a website??? Do you need to have CGI?

you'll need to parse the user input in order to do that. yes you'll need cgi or php.

basically you need an application to read the user inputs and look for the ':' and ')' then replace it with the 'img' tag.

see if this helps you:
http://www.quasigeek.net/~rewritable/smilies.html