I have a new macbook pro and want to copy files

If the drive is formatted as HFS+ (Mac's native format) then you will not be able to access it on a PC. If it is formatted as FAT32 you can access it on both. If it is formatted as NTFS, it will probably be readable but not writable on a Mac.

If you are using this as your time machine drive I would suggest buying another drive and formatting as FAT32 for transferring data. Beware that large drives (1TB or more if I recall correctly - check this before buying a drive) can't always be formatted in FAT32, so be aware of this when choosing a drive.

Hmmn. Far easier, I would think, to share the files via the network (if both machines are on the same network.) Check this link:

http://www.ifelix.co.uk/tech/3001.html

Using the MyBook would be faster if there is a LOT of data, though.

What OS are you running on the PC?