That is pretty cool. You can't buy an iPhone for $25 but you also cannot buy a Raspberry Pi for $25 that has WiFi, 3G, BlueTooth a display, 64GB of flash and 512MB of memory :-)
Anyway, I look really forward getting my hands on an RP.
I think it requires about 5w of power so yes. In fact I'm planning on getting a micro usb solar opwer pack to use with it if I can get my hands on a board.