I've been using Protel SE for several months and though it rarely crashes, it is maddeningly inconsistent and hard to learn and use. Not recommended if you can afford anything else.
A simple and somewhat more well-organized (though barely, and with its own collection of inconsistencies and...
At 433 MHz (a Ham Radio band in North America) there are lots of off-the-shelf parts as well as designs. The last Radio Shack catalog I looked at had a low power 433 MHz data transmitter in it. For a simple single chip solution requiring almost no RF expertise, try RF Monolithics...
Single chip transmitters, receivers and transceivers, with few external components -- RM Monolithics' stuff works nicely. http://www.rfm.com/
Also, Micrel has some parts that look pretty good, though I haven't tried them myself. http://www.micrel.com/product-info/qwikradio.shtml