Where can I find the proper procedure to evict tenants in Pennsylvania?

My tenants are 15 days late and giving me the run around. I have been searching the internet but I haven’t found what I need. Can someone please point me in the direction of the proper procedures and forms necessary to file for eviction and also for recovery of rent? They have the money to pay, but I get the feeling they want me to evict them because they never planned on staying that long. Can I sue them after they are evicted for the remaining 9 months of the lease? I’m in a college town and won’t be able to find new tenants until June 1st 2008. Any help would be greatly appreciated I’m obviously new to this.