Blue Chip MiniBridge is free and you can download it from the Blue Chip Bridge website.  It will teach you the game, let you try out some hands on your own computer and give you an excellent introduction to bridge.  Blue Chip Bridge MiniBridge

The American Contract Bridge League (ACBL) provide a bridge tutorial  which you can download for free from their website. It teaches the various cardplay techniques (promotion, finesse, ducking etc) and all the steps for planning in Trumps and No Trumps.   There are also some hands you can try to test your skill!

Useful material for all bridge students, 1st to 3rd year.

Don't use the sections on bidding because they are teaching the American system which is different to Acol. 
ACBL 'LTPB1'     

There is also a second program which included more advanced cardplay and more on defence. ACBL 'LTPB2'