Here is a sneak peak of the Eyeball Messenger v1.0 currently in beta, built using the yet to be released Eyeball Messenger SDK. Now with federated IM accounts including MSN, AOL, Yahoo! and Google plus support for open standards = SIP (VoIP, Video) and XMPP (IM and Presence).
I can't tell you how pumped I am already, I am now using this instead of 5 other applications = 4 messengers plus our SIP softphone, now I get them all in one app.
The SIP softphone / dial pad is really cool, accessed by clicking on the purple phone button, it works pretty slick. I can use it to call via my Buddy List (as long as they are using SIP) or I can call a SIP URI / real phone number via my SIP / VoIP network. Video calls also use SIP and it's very easy to use, highlight your buddy and in one click you're in business.
I have had a huge amount of input on this design so it's not suprising that I think it's a HOT app, I might be little biased If you are interested in getting in on the beta send an email to the beta program manager = rsc AT eyeball.com, he tells me that he is still looking for a few good beta testers who have access to various SIP and XMPP networks.