You would need an amp of some sort of course, opamp, whatever. Then feed that into a schmitt trigger to get a nice square wave and then detect which mic triggers first and how long it takes to get the second trigger. that might give you a rough direction, but sound waves move pretty fast and arent always super directional, and there are tons of stuff that can affect them.
But I did build a lightning detector that used the flash of light to trigger my digital SLR. I used a fast photodiode and an pic with an ADC so i could set a threshold to handle ambient light. So speed may not be that big an issue anyway