I tested a few applications in the past but all of them were too difficult to handle, didnt work at all or headtracking wasnt availiable.
I wrote earlier in the forum about Stereo Photo Maker,a free program, but there were too many things to prepare to get it working. Now i have a preconfigured settings file that you can download and you can wiew stereo pictures right away.
please read more HERE
Beside others i also tested Sview , also a free program, interesting if you dont have VorpX yet and just want so sneak into how some users screenshots look like, but it has one big disadvantage, it doesnt provide headtracking which can be very annoing.
VorpX together with Stereo Photo Maker does.