Not only 3g capable phone can connect to the internet.. All gprs phone are capable... The only diff is that 3g capable phone is more faster than gprs and edge connection...
How to activate your 3g?
Go to tools, settings, phones, network connections, tick UMTS. Or Dual connection is to auto switch between gprs,edge,and 3g.
Call your service provider to activate your sim for internet and ask for the handset settings via OTA.