You got a good buy since the CMP ran out of M1 Carbines (except for some high priced auction pieces).
Mine is one of the most fun guns to shoot I have.
You need to check out the CMP GSM Carbine Matches, let the gun show you what its capable of.
Join and participate in these forums, you'll get all the information you can possibly get from these people.
Check out the CMP sales for accessarys for your carbine. Good USGI Mags, ammo, bayonets, etc. (got to have a bayonet to go with your rifle, its the law).