I don't think the PG list for '08's is out yet. It's due out this month. They are now working their rankings jointly with Baseball America.
Baseball America published a list of "top 10" for each age group last summer. I think you can still find it on their web site, though you may have to be a subscriber to get at it. The problem is I think they go by age, not by class, so some in last year's 15u class (now 16u) are, like Robert Stock, actually '07's.
Melville is the best young pitcher I have ever seen personally. He is both 16u and '08. I am sure there are others but I can't imagine there are too many out there in his class. Not bad in the field or at the plate, either!
I know in Virginia a web site called Virginia Preps publishes an in-state prospect list, but I have no idea whether it's accurate or not, or how they compile it. But I think they only focus on seniors. I believe they are affiliated with something called Rivals.com that runs similar web sites in other states, so you could try searching for Rivals.com.
None of these lists are ever to be taken as the gospel, but I would suggest you take any '08 lists with an extra heavy dose of salt. Fun if you're on one, but in truth, lots of kids with top talent just don't start making the rounds of showcases that early, and thus will not be on any lists.