Ok I just started loading themes unto my blackberry, but if u are running version 4.1 u need a theme loader, I did not see this info in some of the forums I visited, could not get anything to show until I installed a theme loader, it seems version 4.2 has it's own so here is a link to one
[Only registered and activated users can see links. Click Here To Register...]
just load this on ur blackberry and u r good to go. Hope this helpful to the other noobs.