Links

Scrabble.com

Wikipedia description

How to Win

Game Information
available in many formats

The Classic boardgame ! Personally, I love an old, MS-DOS version called "Scrabble-Deluxe Edition" the best. It plays on modern windows okay.
Then, there is Games.com or Pogo.com which are great for meeting/chatting with friends or new people.
By far, the best Scrabble game is when you get the box out, and open the board on your table. Here is your tile holder,draw seven tiles... and wait your turn!