Blue Cat Audio's Phaser is a free plug-in that is available in pretty much any plug-in format. You can get it for both PC and Mac systems, and it's available in RTAS, VST, Direct X, and AU formats. Just go ahead and download it directly from Blue Cat's site and follow the step by step installation instructions as you normally would, and you're set to go. The interface of the plug-in is much like a few of the other Blue Cat Audio free plug-ins, so if you've got the whole freeware bundle you should be accustomed to this sort of look and feel. It does have a few different skins to choose from if you want to change the look around a bit. The plug-in has a series of simple knob/slider parameters (depending on the skin) that control gain, stages, depth, rate, dry, wet, feedback, and wave shape, from which you have either sine wave or triangle wave to choose from. A manual should not be necessary for use with this plug-in.
Right now I'm running the Blue Cat Audio Phaser as an RTAS plug-in for Pro Tools LE 8. I'm running it on a Mac Book Pro lap top that has a 2.2 Ghz Intel Core 2 Duo processor and 4 GB of RAM, while I run Pro Tools LE with a Digidesign 002 rack version. I listen through everything with a pair of Adam A7 monitors. Even if you don't have that quick of a system, you should be able to handle this and the other Blue Cat plug-ins. You might as well try it for yourself since it's free anyway.
It's definitely more than nice to find a whole bundle of free plug-ins that are compatible for Pro Tools, as you won't find nearly as many out there as you would those in VST format. The Blue Cat Audio Phaser is one of these plug-ins, and is definitely worth having no matter what system you have. While it's not the best phaser I've ever used by a longshot, it still sounds good enough and offers up a lot of control and room to mess around with sounds. If you don't already, I'd encourage you to head over to Blut Cat Audio's website and download their bundle of free plug-ins now!