Just in case you guys are trying to use one external drive for both Windows and Mac environments (as in my situation), here’s something that will save you all the grief and hours of sitting in front of your Macs

1. Download the latest MacFUSE Core DMG file and restart
2. Download the latest NTFS-3g + MacFUSE Tools (and Uninstaller if you want) from Filling the Gap NTFS-3g page via NTFS-3G for OS X Revived Blog
3. Plug-and-play with your external. It should show up mounted automatically. If not, do a quick restart.

Hope that helps.

PS. The steps above is more updated that what was posted over at this MacOSXHints article.

Update 2007-04-28
Grab WinClone if you’d like to backup/restore your BootCamp partition. Great if you’d like to try out Parallels using that WinXP NTFS partition.

Update 2008-08-13
Step #2 above has been updated, which links to the latest NTFS-3G for OS X development.