All you would need to do is have Mac OSX format a "new" external drive as FAT32 (MS-DOS(FAT)) using the disk utility. Once formatted, you will see the disk on the desktop/finder and all you need to do is copy the files over.
If you don't have a spare drive but do have a good backup and you have room on your HFS formatted external drive, then you could resize your HFS partition and add a FAT32 partition to start the copy over.
My advice though for work, get a second USB drive, that way you won't have to worry about theft and you can consider it an "offsite" storage.