Open Source Software Radio

very, very cool:
The Universal Software Radio Peripheral, or USRP, is device which allows you to create a software radio using any computer with a USB 2 port. Various plug-on daughterboards allow the USRP to be used on different radio frequency bands. Daughterboards are available from DC to 2.9 GHz at this time. The entire design of the USRP is open source.

The USRP works with GNU Radio, a free-software (open source) framework for the creation of software defined radios. Both the USRP and GNU Radio work on all of the following operating systems:

    * Linux
    * Windows
    * Max OS X, PPC and Intel processors
    * FreeBSD and NetBSD

All for only $550, See Ettus Research