Ext3 is the right filesystem to use for drives shared between Linux and windows dual boots.

Since NTFS in not writeable from linux yet, I have found that ext3 is the best filesystem to use for large drives that you want to access from both windows and Linux with a dual boot system.
There is a great driver called ext2 IFS. It installs very nicely and configures cleanly.
The only thing I need to figure out is how to turn it off when I boot my windows using VMWare with a raw partition, if I ever figure it out. Then I will want to map network drives to the same place in that case so everything keeps working. I might use shared folders if I can get it to work. I think it is not available in vmware player though.