Adam pretty covered it and the standard U.S. infantry arms were the M1 Garand (.30-06) and the M1 carbine (short .30 round). The CMP is a good place to start and they can be reached at
http://www.odcmp.com.
It may be possible to visit a few gun shops and see what is available. One caution is that many military surplus arms may have been altered or abused and most seem to be overpriced. Look around, ask a lot of questions and good luck. All the best...
Gil