Sound levels when playing music

I have this problem when playing usic on my iPhone, and anticipate the same problem on my iPad when it gets here.

A lot of the songs in my library do not play at the same "level". I am constantly adjusting the volume. Kind of annoying when I have the iPhone playing through the stereo at a gathering. Is there any way to get the iPad to adjust the output to a more constant level? Is there an App for that?

Yes, I know I can go into iTunes and adjust the level on songs there. Would rather not have todo it that way, though.

Thanks,
Jeff

You could try using sound check - seems to have to be enabled on iTunes as well as on your iOS device.
iTunes: About Sound Check
It is putting extra info into the id3 tag from what I understand - and you can turn it off on either iTunes or on your iOS device if you don't want to use it.