Zone Alarm is now offering a free 'Instant Messaging Security Software"
"Instant messaging is being used a lot and people aren't paying attention to the security risks that are out there. People are still way too trusting, and they think instant messaging can't be used against them. But it can."

—Art Manion, Internet Security Analyst, CERT
They say that this will work on any IM client also.

Equally important, the products are easy to use. They provide universal protection, work seamlessly with AOL Instant Messenger, Yahoo! Messenger and MSN Messenger. They protect you regardless of the service or client you use—even universal clients like Trillian.
Get it here.