Hey AtomSoft. I just picked up some RFM12 (not the B, but they are basically the same). I'd recommend them, $5 for a transceiver so it can send and receive if you write sensible software. It does encoding too using basic frequency hopping, so theoretically you can run a few different "networks" in similar frequency bands.
Not that I'm trying to put you off looking at the Manchester encoding but it is hard. Microchip have a fantastic document with further details, look for application note TB045. But basically, you need to run a proper state machine on the receiver in order to conduct tasks such as clock recovery. Manchester encoding done properly is not simply encoding each bit to 01 or 10, though of course it is important to remove DC bias.
I really recommend using a chip that does the encoding for you. This frees up time on the PIC and means you can do useful other things than looping forever waiting for the pre-amble.
As a shameless plug, I just designed a breakout for the RFM12 (it uses 2mm pin spacing, not suitable for a breadboard). Let me know if you'd like some, I'm going to order them from BatchPCB soon. Cost price, I'm not looking to profit! There are some 2mm headers available at Farnell that I plan on using so I can prototype using the modules at low cost.
The image below is the best I can get at during the day, can provide a better one from Eagle later.
**broken link removed**