What is the difference between GPRS and EDGE?

EDGE is the enhanced version of GPRS. EDGE is the abbreviation for Enhanced Data rates for GSM Evolution. It is sometimes called EGPRS - Enhanced GPRS.

In both of these connection types, you are billed for transferred kilobytes, not for connection time. The difference is, EDGE allows transfer speeds up to 236K. That is three to four times more than GPRS.

GPRS is an older technology. You should prefer devices that are cabaple of connecting EDGE networks.

For more information:
EDGE on Wikipedia
GPRS on Wikipedia