I just built a battery powered wireless
remote. It has a 48 key keyboard and
transmits wireless data using the
Manchester Coding method.
I used the Radiometrix 900 MHz
modules and a Dallas Semi 87C520.
I also used the Summit Simulator to
develop it. It works great!
Email me if you need more details.
I did have trouble with the the
transmitter glitching the micro's power.

Buck