I've read quite an old article on Ask Dave Taylor (Boot Camp was still beta) and he says to format the Windows XP partition with FAT; Mac OS X can't browse NTFS partitions.
I have a new MacBook Pro (bought Oct 2010) with Snow Leopard. Can I go for NTFS?
Best Answer
The standard process is to start with a single Mac partition (HFS+ format), then run Boot Camp Assistant. It'll split the drive, and create a FAT32 partition for Windows (which will be converted to NTFS later), and also play some tricks with the disk's partition map to turn it into a hybrid GPT+MBR format (note: this is the reason you should use BCA rather than partitioning it yourself). Then, you boot from the Windows installer disk, have it reformat the FAT partition to NTFS (note: be very careful how you do this, so it doesn't damage the partition map and/or Mac volume -- BCA has instructions, read them) and install Windows. Finally, put in your OS X install disk, and Windows will see it as a driver install disk (incl. a driver to get access to the Mac partition).
Note that Mac OS X can read NTFS, but cannot (by default) write to it; you can change this (see Ryan's answer for instructions), but I've heard of cases where it's corrupted the NTFS volume. Apple leaves this disabled for a reason...