The Google Talk windows client hasn't any invisible status. But for example the ichat client doesn't support invisibility when Adium does support it with .mac accounts (because aim/icq have invisible status).
I made some test with friends on Gtalk (windows). When i set my status to invisible it doesn't change anything i am always visible.
I think this is due to the Google Jabber Server which doesn't support yet invisibility. But i wanted to be sure this is not Adium. If somebody has the answer?
I don' think this is a result of Adium. I can go invisible just fine with Adium/AIM. Goolge Talk hasnt ben out very long so I'm sure its very buggy, or as snarfer likes to say "It eats babies"