In this era of increasing fuel costs and shortages of petroleum-based fuels (see my post on Peak Oil), hypermiling is a brilliant concept that will help you save money. There are a number of websites and articles written about this, so I will not reinvent the wheel. Today, I'll just provide links to what I consider the more high yield sites:
CNN Article on Hypermiling
Overview of Tips for Hypermiling - Not the best website (cluttered with ads), but the information is solid.
Hypermiling Tips from the UK Hypermiling website
CNN Video on Hypermiling