I got the (much reported) spotify app on Ipod touch (2th gen) with 4.2.1 iOS.
I get the crashes everybody gets, so I looked at the memory use of the app.
The app starts with +- 40MB available RAM.
I start syncing and listening to music with the app.
While doing so, I got an memory monitor running.
I can see the device silently running out of memory, sometimes fast, sometimes slow, until it reaches +- 3MB and than the app crashes.