It's a 4 character letter/number combination. There's only over 3000 possible combinations. Relatively easy to crack with enough patience.
It's really the pattern that does it. Even if they had just used letters in and numbers in any random four-digit combination without following a pattern that's 1679616 combinations. Because they followed the pattern of [X or Y][Any number][Any letter][Any number] that brings the possible combinations down to 5200. And it doesn't take a long time to make changes to the code. I would imagine that you could knock out a code every five seconds or so, which comes out to about 7 hours and 13 minutes. When you distribute the task across the Internet, it's unsurprising that results were produced so quickly. For comparison, if they had completely randomized the digits and produced 1679616 combinations, at 5 seconds per possible combination, it would have taken 2332 hours and 8 minutes to fully crack. That's over three months, which would still be a sizable proposition even with the Internet working to crack the codes.
Your not the only one 2 of my friends also have them all :) and i bet thousends of people in the US to :p but i don't :( Now i'm pretty sure i won't win the prizes @ all :p But i aint giving up :) i want it :p