The main contact we had for the Under Armor All-American event I believe came through Baseball Factory. BF is a reputable organization and although we have never attended one, we have heard that they run decent showcases.
BF and Team One also join forces to run the annual Cape Cod High School Baseball Classic, and players who participate there are also labelled as "All-Americans".
I am basically in agreement with Infidel_08, but here's the rundown on the major "All-American" playing opportunities (as distinguished from mere lists that can be found in several additional places):
1. AFLAC-- not kissing up to PG or anything, but this is the real deal. I doubt very seriously that many kids have turned this one down over the years, save perhaps for injury. Actually even injured players tend to make this trip because it is such a genuine and outstanding total experience. Thus you don't see the issue with PG having to move further down the lists just to fill out rosters.
While you can always argue with the player selection decisions, there is NEVER any suggestion that the player must pay something or commit to something to participate in AFLAC. There is ZERO charge to the player for participation. Air fare, hotel and meals are also provided, along with an overwhelming amount of gear and other swag to take home at the end. Not to mention things like getting your picture taken with the annual event honorary chairman (Ozzie Smith this year!). The players get a week of being treated like celebrities, and their schedule is chock full of events both on the field and off.
2. Cape Cod Classic -- Baseball Factor and Team One want this event ultimately to rival the AFLAC game. It was a decent event, but to be honest, not remotely comparable to the AFLAC experience. The rosters did include several AA caliber players including a handful who also participated at AFLAC, plus a few others who have an argument for perhaps being as good as anybody you'll find anywhere. HOWEVER, we were personally aware of a large number of players roundly acknowledged as among the very top prospects who were invited and declined. There were also a substantial number of kids who accepted and then backed out at the last moment, which left BF/TO scrambling for replacements at the last minute. The replacements were good players but not AA caliber, IMHO.
Cape Cod charges no fee and provides hotel and meals for players plus a modest amount of swag. This leaves you handling your own air fare. Accommodations and field facilities were second rate. Attendance was meager. Events off the field were virtually non-existent, and those that did occur were unimpressive. The players were bored and played a lot of poker. Not that elite teenage athletes need their egos stroked any more, but the whole AFLAC celebrity treatment is non-existent in Cape Cod.
3. The Under Armor event rightly comes in for special disdain because it is the only large, on-field event of which I am aware which basically sells you the "All-American" moniker. Under Armor as noted charges $799 plus sticks you with the whole travel bill -- air fare, hotel, meals, the works.
I am sure UA starts by seeking out the very best players in hopes they will attend and lend the event more cache. But when those don't accept, they move on down their lists, and they conveniently forget those who declined to participate. Also, this event has hundreds of players, compared to 38 at AFLAC and a comparable number at Cape Cod. So they have to dig pretty deep to get their desired level of participation. I know for a fact that many UA attendees are not regarded as Division I prospects. It's a cynical exploitation event if you ask me.
I suppose if you are deep down the list, and if you go in with your eyes wide open, there are worse things that can happen to your son than to have a fun baseball trip and come home with a plaque that calls him an All-American. He can be in his hometown paper and show it to his grandkids some day.
But the cheapening of the All-American label is unfortunate, and the reality is that among real baseball people, you're not fooling anybody.
I guess my deepest concern is for those who head out there genuinely believing they are being honored. They're basically being defrauded.