http://forum.baby-gaga.com/about2396301-1.html
Some of the info on this is covered in the thread I linked (called Boobies 101) in this section - it talks about some of the pitfalls of pumping. It can be done for su re- it just really is much iffier than nursin gas far as how long a momma can make it work...but that also depends on factors that differ from one momma to the next too. You might also want to check out a site like exclusivelypumping.com specifically for mommas that are doing it that way.