Sudoku Fever

Have you seen a grid like this? It is from a logic game called Sudoku.
The rules are simple. Every column and row and 9 square grid must have the digits 1 through 9. That's it.
Using logic you fill in all the blanks. This puzzle is from The Daily SuDoku, one of many web sites dedicated to the game. Grids like this are appearing in newspapers and airline magazines next to the cross word puzzles. I brought home a a book of 100 puzzles for Lana and Ariel as a present from my recent trip to Brisbane. The lady I was working with told me of the game and mentioned that on one of her international trips she got hooked and had to throw her book away as it was too distracting!
The Daily Soduko site even has an easier puzzle for children using a 4x4 grid.