I have used the Nordic nRF24E1 in several boards. Has integrated 2.4GHz (900Mhz also available) transceiver and an 8052 in a sub-postage stamp form-factor, with few components and a PCB-track antenna. Really can't be made easier.

In one project I matched it with the FTDI FT8U232BM
to implement a virtual COM port over a USB wireless dongle.

Look at the forum..
http://groups.yahoo.com/group/NordicRF/

or go to www.nvlsi.com

tks
bruce