SoundCloud has updated its iPhone app and with comes a great feature that, now that I think of it, i wonder why it wasn't available before. Turns out that now SoundCloud on the iPhone lets you record and trim audio on the go.
There is also a new feature called Handset mode that records your sounds as if you were in call. It works when you lift your phone to your ear, that way it only records the sounds as if you were in a phone call.
SoundCloud is available for free as a universal app (iPhone/iPad/iPod Touch) in the App Store [iTunes Link].