Formatting a USB drive for FAT32/MS-DOS on OSX?

Hello. I have a USB flash drive that seems to be malfunctioning.

When I put it in, I can see all of the files that I have (as I should), but the size of the files in question equal up to about 240mb. The drive is 512mb capacity, and when I look at the remaining space on it it says I have only 29mb left.

I did at one time use up nearly every mb on the drive, but after deleting things that I didn't need for my daily use/commute, the available space never changed. Even though there aren't enough files to take up space on the drive, I'm still not able to put anything on it (I have a high-res image I'll be using to make large prints, ~40mb or so, that won't fit on my drive).

I was thinking I must need to reformat my drive, but my primary system is a PC running Windows XP (perhaps soon to be Linux's Mandriva, but not yet), but my work computer is a Mac with OSX. Should I just wait to get home before formatting? Using disk utility I can reformat right now (I'm working, obviously...well, I'm posting here, but I'm at work

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). I'm not sure that I'll be able to format my thumb drive for windows systems as well as OSX using this utility (it only gives me options to format for Mac OS extended (journaled), Mac OS extended, Mac OS standard, and Unix File Systems.

I'm pretty sure none of those are compatible with FAT32 file systems (or maybe it's the other way around, but what I'm thinking is that I won't be able to use my USB drive on a windows system anymore if I use this utility to format it).

Anyone have any ideas on the best way to format this?