external hard drive question

So I'm thinking about buying me an external hard drive for my macbook for time machine and to hold more stuff, but i got a question about this product.

My Passport for Mac 640 GB USB 2.0 Hard Drives ( WDBAAB6400ACH )


When it says its mac ready, does that mean I can't use it on vista? I have some music files I still need to transfer but will I be able to use it?

McBie gives some good info here - have a look.