I will say that Gizmo from the tablet to the desktop using video is... not as ideal as it sounds. I found that it barely worked - especially didn't work with tablet to Mac, but would work from tablet to PC - but later iterations of the desktop software seem to fail.

aMSN on the N810 does work. I never got Jabber to work, nor Pidgin - it will work on the desktop, but not tablet to desktop or even tablet to tablet. And speaking of tablet to tablet, Gizmo does work there easily.

Which... doesn't help you. I do have a Gizmo Project account; but no invites to speak of. Good luck, but you're bound to fall into the group like I have... with N810, not happy about the inability to use that forward facing camera for most anything.