Using your iPod for Interval Sessions

Preparations

1. Get Audacity (version 1.3 - might still be in beta, but has been working great for me) and install the LAME encoder for MP3s (instructions).
   
2. Record some soundbites ("Four minutes hard", "One minute easy", "End of session" etc.). A good tutorial on recording and arranging tracks can be found here.
   
3. Build "blocks" - arrange the individual soundbites on the timeline so you have one interval ("4 Min hard" - "one more minute" - "one minute easy")
   
4. Build "sessions" - copy the individual blocks as needed (so you end up with 8* (4Min hard - 1 Min easy)) - make sure to finish with a soundbite "end of session"
   

Set up a session

1. Pick a podcast or music as backdrop and import to Audacity (if using music, arrange the individual titles into a timeline and "compress" the titles into a single track)
   
2. Add the session you want to do and position it on the timeline as required (allowing time for warmup etc.)
   
3. Use the "AutoDuck" feature to lower the volume of the podcast so you can properly hear your instructions (this is a new feature of audacity 1.3)
   
4. Export the session from Audacity, transfer to your iPod
5. Enjoy doing a hard session!