Windows and OSX both can read and write to FAT32 partitions. When formatting the disk, you might need to use a 3rd party program like partition magic due to Windows being unable to format partitions above 32GB.
Just keep in mind the size of your partitions on that drive. Under OSX, you can't read partitions over 127GB in size.
For any other questions, take a peek at this article. It has some interesting solutions to what you're looking to accomplish.