I have the RCA WHP-150 they work great. Got them off eBay.
900mhz (912 to 914mhz)
2 AA size Recharable Ni-Cad Batteries (battery life is great, I use them about 2-3 hours each day and only have to recharge every 2 weeks)
Range is great, much better than any cordless phone. I can get about 4 houses away before I loose signal. (Quite a long distance in my neighborhood.)
Sound quality is what I would expect from any good pair of headphones.
I run them off the Rear Out jack on my soundcard.
The only thing I found that causes some interference is my 900mhz digital phone and the mircrowave, but only when I'm in the same room with them.