no, unforutnaly its not that simple. You have a higher chance that you will get a blue animal from a blue x blue pairing. but you wont infact see a solid number like you would say in an het to albino python pairing. You could very well have a blue x blue pairing and end up with all green snakes. Is it likely? no, but definaly possible.Either way it's a gambel. Your best bet is to aquire a animals that is A. Already blue or B. is showing signs of turning blue. As for blue snakes.
Trooper Walsh of DragonTails has some exqusite blue animals. his prices are not for the faint of heart as i believe starting price is around 7k
Sean Stewart of Herpetologic.net has some blue animals (turning blue) again, his prices start at 6k.
And last but definaly not least Greg Maxwell of FineGTPs.com has a blue x blue pairing that is proven to throw blue off spring. His starting price for unchanged neonates (no promise on sex or promise that the thing will even show any signs of blue) start at 3k. But I would watch his site like a hawk and make sure you get on the waiting list when he opens it up as i know a few people who have been waiting for that pairing for a long time.
Again, understand its a gambel and blue animals are definaly rare so they come with a heafty price tag. I also suggest posting on www.chondroweb.com you will find ALOT more information there.
Good Luck,
JG