NTFS and MacOS

Readonly NTFS partitons are visible from the start in Leopard and Snow Leopard. If you want to have rw possibilities - that's another story.

Leopard: NTFS-3G is good, working solution.

Snow Leopard: rw mode is built in but not used by default. To make it work:
First - check mounted partitions and choose disk-partition number, simply enter in terminal:

mount

Second - if you know which partition is your desired ntfs partition, then check its id (let's pretend ntfs partition is first partition on second disk - disk2s1):

echo `sudo /System/Library/Filesystems/ntfs.fs/ntfs.util -k disk2s1`

Third - ok, we have its id. Now edit /etc/fstab file (or create new if you don't have it) and put there (remember to put there your real disk UUID!):

UUID=your_ntfs_partition_id none ntfs rw

Done. Just restart. Complicated? Well, its not that simple as installing some software but with three really simple steps your system is untouched and everything works. And there is another problem with NTFS-3G - it's not working on SL x64 ;) so for me its useless anyway.