For those on dual-boot systems. I’ve yet to try it tho.
Be careful and read the warnings about EXT3 partitions. If you mount one of those and your system crashes, you stand a high risk of losing your journalized file system (break the nodes). I’ve done it on Linux (my stupid mistake; not a crash) and I basically lost the file system and a bunch of stuff in it. Fortunately, I make backups constantly. Unfortunately, I had to rebuild my system from scratch.
If you want to aces data stored on ext2/2/reiser partitions under windows, I can recommend a pragram called “total commander”, formerly “midnight commander”. You can install a plugin that mounts the linux filesystem readonly, so you don´t mess up that fs.
Homepage: http://www.ghisler.com/index.htm
plugin: http://ghisler.fileburst.com/fsplugins/ex2fs.zip
krizu
I’ve used that fs-driver.org for a while and works very well. Just be careful so each time windows crashes, boot linux to scan the fs. This driver allows me to install windows in a small partition (8 gb) and non-essential windows software and data in linux partition. An image of the windows partition fits in a DVD; each time it brokes, I can restore the partition.
Actually I haven’t used it too much (I rarely use windows), but 2 friends of mine have, and the only problem so far was a terrible mistake: fsck’ed the filesystem while mounted read/write. He wrote something that appeared in the screen (mount / -o remount,rw) before doing fsck without reading the warning messages. He doesn’t understands english well enough…
The message actually said something like “The root filesystem is monted read-only. If you want write acces, type:
mount / -o remount,rw”
Back to topic, this driver works very well, my only complaints are (aside being ext2 and not ext3) the charset (both OSes should be configured with the same charset for our spanish characters to work áéíóúñ) and the hidden files: it doesn’t hide .dot files and folders.
And the next step is…a Linux emulator??? 
Already there: http://www.colinux.org/. Of course I’d rather have it the other way around… when oh when will WINE be truly complete?