Methanol, not methane. Methane is what comes out your butt after a burrito dinner from Taco Bell. Methanol is a from of alcohol.
Alcohol injection is starting to see a rise in popularity again. It had some interest in the mid 70s when octane ratings started to drop and was a means to keep high compression engines out of detonation. Now it is gaining popularity again because of the popularity of boosted applications that generate a lot of heat.
It works because of two factors, the higher base octane rating and the tendancy to be cooler than gasoline and hence reduce inlet charge tempratures. however, alcohol and alcohol blends tend to burn hotter than gasoline and your exhaust temps go up.
Hooking it up can be done as simply as a tank with the alcohol and a vacuum line hooked to a carb, think of something like a windshiled washer set up going to the carb. More involved kits will use a pump that can be triggered via a micro switch attached to the carb linkage to it is more automaticly used at WOT, like nitrous. The most complex systems will be plumbed in using multiple sensors, like late model engines, to detect heat, load, throttle position, etc.