Special pincodes like 15 numbers/letters long are a marketing tool. It seems when you sign up and register for everything Disney it generates these codes randomly. You do this when you register for their site. It will ask you if they can send you advertisements and you need to say yes, here. It seems what works best is going to the vacation planning section of Disney's site and coming up with some vacation scenarios and saving them. If a survey pops up, then take the survey; because, this seems to increase your odds of getting this so-called random special pin code. Signing up for the vacation DVD has been reported as a good way to get these special, well desired codes, too.
There are public codes to watch for as well. Disney Visa may do an offer and Disney may do a public offer. The public offers have been very good this year due to the economy. These codes are usually three letters long.
If you watch the posts here on Dis Board in this forum you will get a clue as to what public codes are being offered and if anyone is getting a special code lately.
In answer to park schedules they usually appear 90 days out; so, May 2010 should be available in February 2010.