Socialcam is the #1 free app most downloaded, and has now surpassed Viddy in the iOS App Store. They've also announced a recent angel round, as noted in Techcrunch:
The race to be the “Instagram for video” is hotter than ever, and Socialcam, the app that spun out of video sharing pioneer Justin.tv last year and was part of Y Combinator’s winter 2012 class, is hustling hard for the lead. The company has raised seed funding from a group of angel investors that reads like a “who’s who” list of tech and entertainment industry heavyweights.
I’ve been hearing whispers about Socialcam’s crazy angel round for weeks now, and I’ve finally verified the full list of the startup’s seed backers.