Wireless media streaming has always been a Holy Grail for AV types, and it appears a few folks have gotten pretty close to not choosing poorly. The AircordAV transmits 1080p over 802.11g using a some strange dongles. This looks like vaporware right now—pretty CG-tastic, but it might be worth a look. Or then it might not... remember ZigBee?
The AircordAV features a base unit that can connect to any home theater component via HDMI, DVI, component, S-video, composite and event SCART for our friends overseas.
AircordAV Wireless Transmits 1080p HD Over 802.11g Wi-Fi [eHomeUpgrade via Engadget]