finster: Not sure, I think it is a 433.92 (on the crystal on the picture is says 433), but im not sure. I have seen some that are marked 433 and 434.. and when I look at the Datasheet it turns out its 433.92 most of the time. Maby check out digikey.com
GSI2: Nice to see what you have done.. But whats that remote with the wires on the buttons? Are you pulling wires as well? What type of switches did you use? I haven't continued with this project, got sidetracked by openwrt. But now I would like to continue. Did you use the transmitter on the remote? Or did you use a separate transmitter? Did you "record" the signals from the remote on the arduino? If so, did you use a separate receiver, or the one on the devices?