SL-NTFS means Snow Leopard NTFS, it’s a Preference Pane that permit to enable writing on NTFS (New Technology File System) disks, format used by Windows.
Before 10.6, only reading was possible, since 10.6 writing is possible too, but disabled by default, because Apple doesn’t officially support it.
SL-NTFS is just an interface on the Apple NTFS driver to enable writing.
Any encountered problem come from the Apple driver and not from the Preference. If you often need to write on NTFS disk, I recommend you to look for a better solution.
Also, you shouldn’t use SL-NTFS and another utility which do the same work, it might cause some trouble.
The installation is very simple, once the .zip archive downloaded, unzip it, and launch the installer package and follow the steps.
It’s designed to be very simple to use. Once the preference is opened you will have this window :
The table list all the available NTFS volume (Internal and External) and the writing status.
To enable or disable writing on a volume simply check the button. If you didn’t enter your password yet, it will be prompted.
After that, the disk will disappear and re-appear in the table, if the button is still unchecked that means the writing on this disk via the Apple driver isn’t possible.
You have the possibility to activate a daemon (program which run in background) that will ask you if you want to activate the writing on the disk each time one is mounted and writing isn’t enable on it.
To do a clean uninstall, I recommend you to use the uninstall button in the about tab of the preference.