1watz

Friends, I am planning to buy a fone. Budget upto 15,000. I have thought about buying a w700i or n 3250 or k750i. I have other fones in mind, too. But problem is that i don't understand what is Symbian. (1)watz the diff. btwn s40,s60 and other symbian levels? (2) what is the use of...