Thats right, it won't work!
I looked into this before I purchased my iPod because I am a dual-platform user.
I will break it down easy then get a little more detailed.
PC formatted iPod works with both PC and Mac
Mac formatted iPod does not work with PC
So if you want to use it across both OS then you have to format it on a PC. also, you will only be able to sync your iPod to the media library on th PC. You cannot have a PC formatted iPod with your media library on a Mac.
A little more detailed. So here is the breakdown.. you know when you format a hard-drive? Well, when you format a drive you have to select the file system the drive will use. The most common of which now are NTFS FAT & HFS+, probably in that order.
Windows (since NT) use NTFS. this file system has many advantages over the previous file system used by windows. And was standardized for this reason. However, the NT File System (NTFS) is a proprietary of Microsoft, as a result they can say who can (or can't) use it. Apple Can't!
File Allocation Table. This is a file system that keeps track of where all the pieces of a file may land on a hard-drive (one file could be split into thousands of pieces scattered across the drive) This file system does not support any advance features like NTFS or HFS+ do. This file system was used by Dos and later FAT32 by Windows95. This file format is used and can be read by bot Windows and Mac computers.
Hierarchical File System. Was developed for the Apple Macintosh and is the most advanced common use file system in use today. Origionally HFS, the + was added around the time OSX hit the stage. This File System has all the features of NTFS and some other very important ones. 255 character file length names, you can get some big file names and I hate when windows automatically shortens them. The use of more unicode characters in file names, such as ! @#$%^&*(_) and all those great [email protected]
#%!ng characters. Greatly improved searches with metadating and an all round faster more efficient drive.
There is way more info here ---> http://en.wikipedia.org/wiki/HFS_Plus
So what does that mean?
A PC formatted iPod uses FAT, so it can be read by both PC and Mac. However it doesn't support larger file lengths or better searching. (I don't think the music searching changes because iTunes takes care of that, but if your using it as a hard drive it may make a difference)
A Mac formatted iPod uses HFS+, so PC's can't get into the bugger, cus Windows has no way of interpereting that HFS+ Data.
To sum it up:
As stated earlier.. I work on both Operating systems daily. I have tons of hard drive space and both systems are pretty good. so it wouldn't really matter which system I synched with. After considering everything tho, I now sync my iPod on my Mac.
Well, you will discover eventually that there is just about nothing that can compete with your mac. Afterall, thats why you bought an Apple iPod right?
Hope that was of help, I know I went on there, but I wish someone had straightened me out when I was scratching my head over the same thing.