Everything that you ever wanted to know about drill bits:

http://www.jjjtrain.com/vms/cutting_tools_twist_drill.html#4

http://www.boatbuilding.net/article.pl?sid=06/03/15/1512243



I recommend that you purchase and try a couple HSS rated drill bits. High Speed Steel, sometimes abreviated HSS, comes in a variety of different grades generally used in the metalworking industry to make drills, turning tools and other tools to cut metal. In woods and plastics, all grades of HSS far outlast the cheaper Carbon Steel or Stainless Steel. Tools made of High Speed Steel will always have HS or HSS stamped on them. Don't be fooled by imitations!