$39 From the apple site: Put your slides, movies, photos, and everything else that fills your iPad 2 screen on an even bigger screen — your HDTV. The Apple Digital AV Adapter mirrors exactly what you see on iPad 2 so that everyone in the room can enjoy it on your widescreen TV, video projection screen, or other HDMI-compatible display. The Apple Digital AV Adapter also supports video out for iPad, iPhone 4, or iPod touch (4th generation). Also has 2nd plug to charge while in use.
Well, technically that's the whole point behind it. For instance, my Infuse records videos in HD, and can transmit whatever is on my mass storage card (powerpoints, videos, etc..) The only thing i haven't tried is using it for skype. You do have to have the phone plugged into a wall outlet to support the HDMI out.
My roommate just got the sprint EVO 3d and it mirrors everything thats on the phones screen to the tv. There's no hdmi port BUT if you go to t mobile you can get there micro usb to hdmi cable adapter. It plugs into the charge port and transmits hdmi through it. (sprint doesn't tell you it can do this) the adapter also had a port so you can charge at the same time. Once its hooked up to a hdmi port on a monitor it displays everything the phone does. Hope that helped. My regular EVO will only display photos and YouTube unless you root the phone.