Qik has been on select Windows Mobile devices for awhile now, but the beta has been opened up for everybody without the need for an invite. You can check it out at http://qik.com, but be warned it might just start playing video automatically (which is annoying). The “Beta” part of Qik is no joke -- it works very well as you can see from the above video but it also has some account management issues to work out (like switching phone numbers associated with an account). Qik currently only works with a few Windows Mobile phones, the Motorola Q9c, Q9h, and the Samsung SGH-i600 and BlackJack II. More should be coming in the future, though.
Oh yeah, what does Qik do? It's a live-video-streaming app that lets you share videos either with the entire internet (as above) or just people you select, plus the videos are archived for future use (as above). All in all, it's pretty slick. They've added a heap of new features with the new beta, which you can find detailed on their blog.