Hey,
Rooting your phone doesn't change your service provider/carrier's plan with you. What rooting does, generically, is that it gives superuser access to your phone. (Which means you can do pretty much anything with your phone). Although it is a risky process at times, rooting could be pretty fun and useful too. The only program that you can root your phone with (from my understanding) is odin. There are many tutorials throughout these forums or on youtube on how to root so you should check those out and make sure you do everything correctly.