I need to set up a new iTunes account. How can I get all my music from the old account on to the new one??? Thanks../

I have just bought an ipad 2 and wish to set up a new account as now I won't have to share with my sister. I want to get all the music off my current iTunes account & put it on to the ipad/new iTunes account. I'm not too sure how to do this though.... Please help lol :-) x