I use the fleetguard strips, I think they're the most accurate way to test everything, plus they have instructions and color patterns to match your test strip to.
For the pH, any pH test strip will work.. but the fleetguard strips have a few other tests on them, coolant hydrometer reading, and the two chemicals that need to be crossed onto their table to know what you're SCA count is. I don't have any links handy as I lost some of my bookmarks.
I think you're supposed to test it when the engine is warm too.
Someone will chime in with some links.