Is there an app that you can listen to for the duration of a 5k that tells you start/stop for walk/run intervals? I guess it would be similar to c25k but I can't do a 5k in 30 minutes yet and want to eliminate the 5 min warmup and cool down (during the race anyway). Does this exist?
I used Zen Lab's 5K app and you can fast forward through the warmup, but it's done by time not distance. Agreed an HRM or Garmin would be the easiest thing to set to do that, but if not then I'd search GooglePlay for a plain ol' stopwatch app or some type of timer app that you has options to set with audible 'alarms' to go off periodically.
I also use Runkeeper with an iPhone. I don't know if it would work with an iPod touch. I don't think it would be able to track distance, but it might be able to do intervals based on time. You can install the free version and see if it does what you want. Good luck.