The main difference being RIP and IGRP are distance vector protocols; EIGRP is more of link state protocol. Then there is a difference in their operations, times (like updates, refreshes, etc.), how they keep track of routing tables, etc. I talk more about routing protocol's different routing tables in this expert response.
You can find a lot of information off the Internet for these protocols. I would suggest you to check it out on cisco.com, and let me know if you have any specific queries on these protocols.
This was first published in October 2006