First let me thank everyone on these forums. After countless hours of reading and testing, I have finally succeeded in creating a program I have thought about for a long time.
I have built a "combat assist" program that basically tracks what is happening with my character and my target. Spells, buffs, runes, cooldowns and such. It then decides what is the best next action. At this time it does not actually send any keys to WoW. I am looking into using PostMessage, but want to be sure I am not endangering myself with that.
My main focus now is working on adding a PTT (Push To Talk for those that use Ventrillo) type functionality. My program runs passively in the background, but if a key is held down the combat assist app would actually send the keystrokes to WoW. Once the key was released, it would stop sending keys. This would allow me to engage or disengage the "combat assist" only when I wanted it. The entire time the program would remain in the background.
I assume I will need to put some type of keyboard hook in place that would identify a specific key being pressed and then PostMessage to my combat assist app that the key was being held down or released.
Doing the research now on putting this together and any thoughts would be greatly appreciated.