Thanks a lot for Ur answer. I do not know too much of

other products but I know Jabber more than most people.

I visited Jabber Inc. at Denver a few months ago and we are using Jabber Chat software to do some integration.
I remember they said that Google IM uses XMPP protocal too.

But some times enen if two companies use the same protocal, they may still have some problems to talk because the low level Interpretation/implementation may have some difference.