I'm in the process of converting old tapes, compilations and others, into waves prior to encoding to aac files.
Volumes are all over the place and I was wondering if running the waves thru Wavegain would solve the problem.
I know that this is not a lossless process and would keep a copy of the original waves, compressed using Wavepack.

auldyin

Yes, wavgain would be a good solution.

You could also compress the originals using Wavpack, use fb2k's replaygain scanner to scan the wavpack files and then convert using fb2k's diskwriter with ReplayGain enabled.

dev0,
Would this mean that the aac files would all have the "same" volume for use on an iPod?

auldyin

Yes. The ReplayGain values are saved in APEv2 tags to the wavpack files.
Volume is adjusted upon transcoding by foobar2000 (if the ReplayGain checkbox is checked in Diskwriter options).
The loudness of the AAC files will be the same as when using WaveGain.

This may be a really silly question but how can I tell if the APE2 tags have been written?

foobar2000 writes APEv2 tags to WavPack files by default. They will certainly be created when you use ReplayGain with foobar.