What is a good cross-platform Instant messenger service?

I like Pidgin, myself. There are a couple of other freeware chat clients.

I like Adium.

Thank you Nullo, I will try that.
Crisw.. the link you provided is for Mac OS i have pc but ty.

Trillian is another with a wide variety of options.

You can also use Meebo with several accounts, originally it was browser based so it doesn’t always require an installation to use.

I use Trillian.

PIdgin for simplicity.

Trillian has video messaging on MSN.

Trillian gets my vote

I second Trillian.

I have used nothing but AOL Instant messaging from day one.

I use meebo, it works pretty cool.