What do I need?

Here’s my situation: I’m trying to help out a friend hook up a network in three different locations. The first location has Pacific Bell DSL installed, and it comes into a punchdown with 5 lines running to it. What do I need to network 4 computers together, and let them all share the DSL connection for internet? Secondly, there will be DSL installed in another location, seperate building, and I need to network those 4 computers together have them share the DSL connection for internet, but how do I have that network see the network at the other location? Do I need to run some sort of communication media to that site?