I've been a beta tester often for other (non-game) programs. It's not particularly hard, but you have to resign yourself to the fact that the program may not always run as expected and may sometimes crash. You don't have to be a programmer, but the ability to describe how problems arise fully is useful so that any reports are useful to the developers. From LDW's beta testing application:

"We especially like to have people with a good eye for bugs and typos, who are willing to devote time to carefully examining the game and providing detailed comments about their testing experiences."