There are manufacturers out there that make multi bit tools. One of mine is made by Hitachi. It consists of a holder with a collar. A flip bit goes in the business end. One side has a drill ( with countersink ) and the other side has a phillips tip. You drill your hole, pull back the collar to release the bit, flip it, and now you have a driver.

Here is a Dewalt system: http://www.woodworker.com/cgi-bin/F...mp;search=Drive%20Drill%20Bit&smode=