there was a thread on this earlier, about 2 weeks ago...
sears sells these fancy diamond coated bits for $6.99 for a 2pc set. one's a round bit to do the "drill like" pilot hole, and the other to cut away as if you're using a jigsaw..without the jig..
http://www.sears.com/sr/javasr/produ...id=00953161000
Craftsman 2 pc. Diamond Point Set
Sears item #00953161000 Mfr. model #5007150-50