A really good resource for rush is at
http://www.tke.org/rush01.html
I was the Pledgetrainer for my (coed)fraternity my senior year. My advice is to balance the educational part of pledging with the fun. My new members had a class every week for history & chapter info, and also so they could ask questions, etc. Each week we also scheduled at least one activity that was purely social- (this was something my frat didn't do when i pledged) and i saw that the new members became exceptionally close to one another. (Much more so than previous pledgeclasses). They also felt more like they belonged to the entire group.
Good luck, i know this is a lot of work!!