If you're like me, a little duct tape and heavy-duty staples go a long way in running phone and cat5 cable at home. Of course if you want to do your wiring the right way, Mavromatic has a tutorial about getting dual service out of your cat5 cable. The article states:

This post is for home owners out there that either forgot to pull more Cat5e cabling and for the home owners that had a builder that wasn't tech savy. This "HOW TO" will show you how you can take a single Cat5e cable and turn it into both an ethernet jack capable of 10/100Mbps and a two line phone jack.

Read HOW TO: Wire An Ethernet And Phone Jack Using A Single Cat5e Cable