As of Ubuntu 7.10, we now have read/write access to NTFS drives via ntfs-3g. But what about the other way around? I just needed that ability today to get a file from my linux install. Since I'm too lazy to reboot twice; and since windows boots up very slow, I don't wan't to do this everytime I need a file from the other partition.
A bit of google searching and I found this app called the 'Ext2 Installable File System for Windows' which allowed me to mount my linux partitions to my preferred drive letter. It gives me read and write (root) access to those files - very cool.