I was a bit nervous flying with guns the first time ... until I actually did it and realized how simple the process was. I had an entire dialogue ready for both the check in desk as well as the TSA agent. The TSA agent especially looked at me like, "dude ... why are you still talking. This ain't my first rodeo."
Aside from Titleist's excellent and comprehensive link, here's a couple more direct from TSA:
Another point to note ... The amount of ammunition you're allowed to check in actually varies from airline to airline. Some limits it to 5lbs or 11lbs, and some didn't have a formal limit so long as the luggage didn't exceed the weight requirements of checked luggage. Generally most airlines do limit you to about 11lbs. I would still recommend calling ahead to make sure a few weeks prior to your flight, just in case you need to make other arrangements. My 9mm ammo barely got to class a few weeks back for Handgun 2 in Portland.
Edit: should also mention, make sure you have a hard case that is REALLY secure. Invest in something decent. I bought a Hardigg (now owned by Pelican I believe) Storm case from LaRue a few years back that came with a perfectly fitting soft case for a couple carbines. Although it was somewhat overkill since I was flying to a Handgun class, I used the Storm case without the inner soft case, and put everything in the hard case from my range back and all accompanying kit, along with my pistol in a Nano Gun Vault 1911 Hardcase. Key lock on the gun vault (which is where the red firearm card the check in agent gives you will go), and two padlocks (Masterlocks, not TSA locks) on either side of the Storm hard case. As you've probably read elsewhere, no one other than you should be able to access the contents of that case. TSA should not be able to get in there without you being present. Also, due to the size of the case, it may come through the oversized luggage carousel. But that too may vary. When I arrived in Portland, I stood by the oversized carousel for what felt like an uncomfortably long time (given the contents of what I was waiting for) and it turned out that the luggage was waiting for me at the airline's luggage office at the end of the hall as they wanted to check my ID. Not so when I flew back to LA. Just something to keep in mind.