There was talk about SIP-support to be built into the existing telepathy-framework "soon"... Unfortunately, this was some months ago.
http://telepathy.freedesktop.org/wiki/ still reads "Telepathy-SIP: Based around the sofia-sip library, should be released by Nokia soon..", an interesting thread dating from Oct 2006 at http://thread.gmane.org/gmane.comp.h...784/focus=5794 makes us hope integrated SIP-support is on its way... Does anybody know if these projects make any progress? Will a result be available for the 770, too?

(It would be so great to have a drop-in solution that integrates nicely with the existing contact/IM-applications instead of one stand-alone client)