Here is a data file captured from the air for people without RF hardware:

• http://ossie.wireless.vt.edu/download/capture/npr_iq_sample.dat - FM Broadcast station, binary big endian, 16 bit I, 16 bit Q, 256 ksps.

• Additional files with extension .dat.zip and .dat.bz2 are available at  http://www.csun.edu/~skatz/katzpage/sdr_project/sdr/

Unfortunately, files from KD7LMO are no longer available. Bad news :( -  http://lists.gnu.org/archive/html/discuss-gnuradio/2009-04/msg00390.html