We have a confirmed report in EGM (Electronic Gaming Magazine) that the Nintendo Revolution will most definitely be Wi-Fi capable.

Quoted from EGM, " While the look of Nintendo's next-gen(eration) console (code-named Revolution) remains shrouded in secrecy, the company has recently provided some details on the guts of this anticipated machine. The power of the Revolution will come from two sources: a processing chip (code-named Broadway) from IBM and an ATI-produced graphics chip (called Hollywood). The new console will also feature built-in Wi-Fi and be backward compatible with the GameCube--the latter being a first for any Nintendo home system.