Aaaaarrrrrgh! Aren't you guys paying any attention? Most road bike double cranksets come with a 130mm bolt circle, which means the smallest chainring you can get is a 38. A compact crankset is 110mm which lets you go down to a 34 tooth ring. Mountain bikes have much smaller bolt circles and thus are able to use smaller chainrings. Got it?

The other way to approach the problem is to swap the rear derailleur and cassette for a mountain setup. If you like really tight gear spacing, then you wouldn't like this, but it does allow you to go up to as much as a 34 tooth rear cog.