Wes, I think CMP is still selling M1903's. They are not in top condition, but would be OK for a starter. Check
www.odcmp.com for info.
You can also hit the shows, but be careful of both faked up guns and fake stories. Also a reminder that single heat treat (SHT) rifles (aka "low number" with Springfield serials below 800,000 and Rock Island serials below 285,507) were not always heat treated properly and some have burst. Most collectors recommend not firing these, both because of the collectibility and because of the potential (if low) risk.
As to books, Brophy's is the best and is still available. I think it is called just "The Model 1903 Springfield". Good books are pricey, but the cheap ones are often full of errors and sometimes almost unreadable. Real research takes time and money and we should be willing to pay for that. The cheapie guys just regurgitate stuff from the gunzines and from other books, almost always without credit.
Jim