Space.com: Cosmos 1, First Solar Sail Satellite

With a big aluminum sail (or sails) connected to a satellite, and using the sail to capture the solar wind you can practically go anywhere the wind reaches. For now, just around the earth, but later, this could be a cost-effective way of going around the block -- and back.

This is an idea which NASA has been toying with for the past 30 years and has been featured in Star Trek (The Movie) as well as in Star Wars (Episode 2).

--andoy