The following article provides most of the instructions on how to setup authnz_external and pwauth on Ubuntu Hardy.
General Updates * Decrease in call set-up failures and dropped calls. * Significantly better battery life for most users. * Dramatically reduced time to backup to iTunes. * Improved email reliability, notably fetching email from POP and Exchange accounts. * Faster installation of 3rd party applications.
MobileChat supports the following protocols: * AIM/ICQ/.Mac/MobileME * Windows Live/MSN * Yahoo Messenger * GTalk * Jabber/XMPP Multiple Accounts