A good place to start if you have a new idea is discussing it on the 'primenumbers' yahoo group - there are plenty of people there who can comment on whether what you have is a good idea or not. There are also a few people here with expertise in sieving algorithms.
Secondly, regarding implementation, manipulation of large numbers is typically done via a library like Gnu multiprecision (GMP) or George Woltman's GWNUM.
If you can show you have a good idea, and can implement, only then might it be considered how to integrate with PG. Steps one and two are a lot of work in themselves :)
Proud member of team "Aggie The Pew". Go Aggie!
3073428256125*2^1290000-1 is Prime!