Changing Keyboard (Hardware) AZERTY to QWERTY

That's not a user-serviceable part, so you're going to have two problems replacing that keyboard:

1 - You won't be able to order the part unless you're in GSX.

2 - You'll probably (but not definitely) void the warranty by replacing it.

The good news is that you don't have to replace the key-board, you just have to rearrange the key tops and change the input method.

There's a web-page that explains the process better than I can:

http://www.chimoosoft.com/dvorak.html

Just be very, very careful when pulling those keys off.

17-inch MacBook Pro Mac OS X (10.4.8)

Take a look here:

http://www.ifixit.com/