I configured today Bitlbee to use Skype, Facebook, Twitter and Google Apps.
Skype may have been the most laborious of these — it has to be ran using VNC server when on a remote server — but Google Apps took more time for me since I didn’t find updated documentation for it.
It’s configured like this on Bitlbee 3.0.5:
account add jabber firstname.lastname@example.org
account jabber set tag g
account g set oauth on
account g set ssl true
account g set server talk.google.com
account g set port 5223
account g on
After this you just need to follow the link Bitlbee will provide for you to authenticate using oauth.