I play a straight tenor trombone in my schools jazz/pep band and play tuba for marching/concert band. I sometimes play the schools bass trombone just because and it is quiet more challenging than playing low note on the tuba! Oh buy the way, im thinking of getting a Eb Alto trombone, does anybody know the positions?

Alto trombone has seven positions just like a tenor or bass. They are just much shorter than you are used to.
http://www.pittstate.edu/music/kehle/altofingeringcharts.html