I looked everywhere for an online copy of the Samaritan Pentateuch and could only find dead links... until I stumbled upon the first page of an article scan in JSTOR that got me to search for "Samaritan Pentatech" in latin. I had looked everywhere in English and then in German, but Latin was the winner this time.
Page scans: Google Books
Now, this is from the 1790's, obviously a bit old. But in the few chances I've had to compare it to modern scholarly works on the SP they've matched up perfectly. If you would like it in book form you can get a very reasonably priced copy of a recent work on Amazon, but Von Gall's work is the current scholarly edition that I am aware of, but I could be wrong.
Also, if you would like to draw more deeply from Jacob's well, you can download page scans of the Samaritan Targums -- just be aware that there are some problems with this text... like they're in Samaritan script, among other things.
Thanks to this blogger, I now have a copy of Gall's critical edition of the Samaritan Pentateuch. This is (still) the only critical edition around.
Have you ever used the Samaritan Pentateuch before?