I am trying to develope an instant messaging system for my website and I wanted to know if I can design it to interact with ICQ, AOL IM, Yahoo IM, MSN IM, etc. Can it be done, and if so, How?
I dont think this would work. Your trying to create an instand messenger for your web site so obviously its web based. ICQ, AOL and MSN are all GUI based and run on your local machine where as yahoo and a few of the other chat sites run using applets. These are two differnet concepts.
If I am right in thinking that you want your users to log into a live chat room on your site and talk to each other then you would be best to do this using an applet (Java applet) like yahoo chat but I dont think it would be possible to make it interact with yahoo chat or any other chat service as you would have to have detailed knowledge of how they are coded!!
Yeah you're best bet would be to code a instant messenger program separate from your website and then have your users download it. You could connect to them all that way. Trillian does.