Digidesign's AIR Talkbox is a free plug-in for purchasers of Pro Tools 8. You can't use this plug-in in any other DAW, as it is designed by and for Pro Tools and isn't compatible anywhere else. You can't even use this with previous versions of Pro Tools, as you can buy it - it simply comes installed with Pro Tools 8. You don't need to do anything to install it beyond installing Pro Tools 8, as it takes care of installing the free plug-ins during this process. The interface of the plug-in isn't convoluted at all, as it has the same look and design as all the AIR plug-ins do, which stands for Advanced Instrument Research. In terms of parameters, you've got knobs for vowel, envelope depth, format, and mix, as well as sections for LFO and envelope. The LFO section consists of parameters for rate, wave, depth, and a button for synch, while the envelope contains those for threshold, attack, and release. There is a good amount of control available here without it being hard to use, so I don't believe that users will need a manual.
Right now I'm running the Digidesign AIR Talkbox on a Mac Book Pro lap top that has a 2.2 Ghz Intel Core 2 Duo processor and 4 GB of RAM. I run Pro Tools LE 8 with a Digi 002R audio interface most of the time. While I've run Pro Tools 8 on an HD system as well, the AIR Talkbox plug-in isn't one of the AIR plug-ins that I've run on an HD system. I've only had a need to be running one instance of the AIR Talkbox plug-in at a time in Pro Tools - really just to see what it was all about. I haven't yet had a need to run more of them than this, so I can't really speak to how well it would perform under harder conditions...
Beyond having Vocoder plug-ins available in my suite, I don't really have too many talkbox plug-ins, so I was happy to gain the Digidesign AIR Talkbox when I got Pro Tools 8. I'm happy that I upgraded as I got a whole bunch of free plug-ins that sound good and are very useful. While generally not the most practical plug-in to use on a daily basis, I can definitely see it coming in handy now and again if someone is you're looking for a talkbox like effect. There is an extravagant amount of versatility here, but the sound quality is more than adequate and there is definitely a good amount that you can do with it. If you have Pro Tools 8 definitely check out the AIR Talkbox and the other AIR plug-ins available in the suite!