There are no work around methods. The iPhone does not allow apps to run in the background. I know what you mean when you say about the iPod feature still being able to run in the background although this is allowed for the following reason :
The iPhone is a phone and and iPod. The whole system is designed to ensure that these two functions work above anything else. By not allowing apps to be run in the background, apple are able to ensure that the two primary functions of the iPhone still work, phone & iPod.
I'm afraid there is no other way. This is one reason why the iPhone os is a fairly stable system.
