There are many resources offered in order to learn to play bridge.

ACBL Online Intro to Bridge Classes -- online introduction to bridge course offered by the ACBL

Free Trickstarter Bridge Class -- free online one-hour crash course about the basics of bridge offered by the ACBL

Bridge Base Online -- free online resource to play bridge, practice bidding and watch international events

Learn on Your Own - a variety of websites and books recommended for the new player

Bridgeclues.com - daily free bid and play problems