Figure out how much money you are working with, what's your budget for the dvd player, and then go to Circuit City or a reputable electronics dealer and have them take the time to explain some of the features. If that doesn' t help clarify and you still aren't comfortable yet after speaking with someone and looking at different models, do some more research then go buy.
Personally, I think it is the stores responsibility to help educate a customer if they aren't totally up to speed on a product, features and the latest greatest shit available.