10.6: Enable native NTFS read/write support – Mac OS X Hints. Very useful for those of us with Bootcamp running so the one machine is a Mac and a PC all in one. Slightly spooky, but it works very well.
The hint works straight out of the box: it is much more useful for me to have the Bootcamp partition available R/W all the time. I just have to be careful not to fiddle with it too much.