How can I view the music stored on my iPhone?

I am using itunes match with mixed results but I have >100gb of music and when I'm in the car I want to see what local files I have available to listen to (because streaming over 3G just doesn't work - its too unreliable). How can I see what music I have actually stored on my iphone and is there a decent way to manage it - rather than having to trawl through iphone and select which files I want - I honestly can't remember which ones are stored locally-surely I shouldn't have to remember?

Many thanks for any help.

Stew