virtual chatting on a Mac?

I am not a complete newbie to the Mac world, just new to chat rooms and virtual chatting. There are a few things that I have been wondering concerning Macs and chat rooms.

First, I am wondering if I need to have some kind of antivirus/spyware for this. I have heard that there is some kind of malware that Macs can get thru ichat......how do I avoid getting this on my computer?

Also I am wondering if there are any good chat clients other than ichat. I have tried Yahoo instant messenger, and it is ok except for the fact that the mac version does not allow me to hear audio in chat rooms. Is there another chat client that would allow this?

Thanks in advance for any suggestions.

See the antivirus thread at the top of the page. You are very unlikely to get malware from ichat.

You won't need a antivirus/spyware program

Try Adium it holds AIM, MSN, Yahoo and more
There is also MSN, aMSN, AIM Messenger, Jabber and more. I suggest you go to Apple Downloads then click on Email & Chat to find chat programs.

It's also good to try them, if you don't like them, find another.