What is the best way to take pre-recorded sound (ie. voices, dialogue) and add it, in computer, to an environment with a particular ambience (ie. concert hall, news room, small bedroom, kitchen, etc.) Also, what software should I be using for ease of use in this process? Forgive me if this is a easy question for most of you, but it isn't so obvious for me.

Audacity is free and will do all this. You'll need a reverb plug-in, which I'm not sure it has. Audacity does accept standard VST plug-ins though.

I don't know if there are good, free reverb plug-ins.

2- You could play the sound in a room with the right reverb, and record it. I believe this is how they did the sound for American Graffiti (how Walter Murch added reverb to the radio sounds). Studios also used to have reverb rooms for exactly this (when reverb hardware sounded really bad).

This method was also used on LOTR1 (lord of the rings) for some of the sounds, albeit with really expensive gear. see the extended edition.

3- Another method, which might work: If your computer has sensaura bundled with the on-board sound card (on the motherboard), you could figure out how to record the effect from it.

Quality won't be that great though as on-board sound tends to have a lot of hiss and pickup random noise from other computer components (i.e. there may be noises that correlate with network and hard drive activity). There might be a way to record it digitally. If the motherboard has digital SPDIF output, then you can record it if you have a corresponding sound card.

My Sound Blaster Audigy can do this with EAX software that came with it.

Thanks guys, I will try your suggestions; though I will probably be using audition or goldwave.

Dwight, you'll have better result with a better convolution reverb, something like what Sony offers in Acoustic Mirror (free with Forge) or Waves IR3 system. These are real ambiences, not processed, and they sound wonderful. I suspect I've got over 1000 rooms in my collections now. If you get the Sony or WAVES, let me know, I'll share some with you. Both the Sony and the WAVES will open in Audition.

Thanks Spot, I will be getting Sony very soon. I will be in contact shortly (via your VASST email).