Vito Technology are celebrating being 7 years old by having a sale of their products for 7 days where each application costs only $7.
Vito have a few apps that might be of interest to Windows Mobile users, such as their metronome, but a couple of apps really stand out (especially at $7).
This application has a bunch of useful editing functions.
and Vito SoundExplorer
Another application for performing a variety of sound tasks including encoding from WAV to MP3,