[spidergawd]

Also, I believe the file size limit of a .wav file is about 4 GB, or roughly 6.8 hours at 16/44.1 stereo, but some programs/file systems may have their own limit. I'm not sure about Audacity.

One more thing, and I know some people are afraid of the command line, but it's actually much easier to use something like sox:

sox file1.wav file2.wav combined.wav