If you run Limewire or other file sharing programs, you will most likely corrupt our iPhone software. Is this true? Seems to me that Apple wants to steer everyone to iTunes Store and away from file sharing, so it could be garbage.
I would avoid Limewire at all costs. I'm not saying you will corrupt your iPhone but all the music you get from p2p utilities are garbage quality and you will most like catch some sort of virus or trojan. Eventually.
There are other methods to getting high quality music such as iTunes and other methods we won't talk about on these forums. Just do some research.