|You cannot run two DSL modems on the same phone line. Depending on which type of modem you get, you will have several options:|
1. If the modem has several ethernet ports, you just need to have ethernet cards in both PCs & connect to the modem via ethernet cables.
2. If the modem only has a single ethernet port, you will need to buy a router (which will act as a splitter). Plug the phone line to the modem, connect the modem to the router via ethernet cable, then connect the PCs to the router via ethernet cables. Once again, both PCs will need ethernet cards.
3. Another possibility would be to get a wireless router. That way you'll have the option to either hard wire both connections as described above or hardwire just one of them & install a wireless PCI card (or USB adapter) in the 2nd PC.
Some DSL modems are "all-in-one"...modem/wired router/wireless router in a single package.