There is wireless HDMI, but it can't officially be called that because it isn't licensed by the HDMI licensing bureau. It's called either Wireless HD or WHDI. DVDO makes one called the DVDO Air. That will work only in the room, it won't go through walls.
Cameron was also wondering if he could run a long HDMI cable instead of using a wireless solution, since his source equipment is in another room. Scott finds that if he's got a short cable run, the cheap HDMI cables work great, and he could find them at Monoprice.com. For a longer run like Cameron plans to do, he'll want something higher quality. Since it's digital, it should work even at longer distances. Ross has a 50' HDMI cable that works great for him, and that's even longer than HDMI recommends.