Difference between Prepaid SIM card vs SIM card?

I'm going to purchase a Blackberry (Curve 8900 Javelin) phone but require a SIM card. The phone has many available features like internet, GPS, etc. I was wondering if these features can still be used on a prepaid account or only on a data plan. I've used only sprint or verizon my whole life so i'm still not sure how SIM's work...I don't really want to get a 2-yr contract right now... any advice would be helpful