The maximum volume/partition size for FAT32 in Windows XP and Vista is 32 GB. (XP and Vista can read larger partitions but cannot create or format them.) If you want the whole drive to be a single partition or just a few large partitions, you'll need to format it as NTFS.
You might be able to get Partition Magic or a similar utility to format the whole drive as a single FAT32 partition, but unless you need to use the drive with an Operating System that can't read NTFS there's no good reason to do that. If you do need it formatted as FAT32 for a non-Windows operating system, you'd be better off formatting the drive from within that OS.