Bitlbee has instructions on their front page for using Bitlbee with Google Talk, but they weren't quite right for me.
Using the im.bitlbee.org public server, the way I added the account for Google Talk to my Bitlbee account was:
account add jabber firstname.lastname@example.org mypassword talk.google.com:ssl
Their instructions talk about using the port number 5222, but that only caused problems for me. The ssl seemed necessary, though.
There's really no reason I need to be part of another IM service, but I just don't like feeling left out.
Also, Google seems to have disabled inter-server communication with other Jabber servers, which strikes me as a pretty lame but understandably corporate thi\ ng to do.