I checked on this not too long back during the beginning of the Voice Acting 'Hub' thread, because I posted a lot of mic and recording information, which can also be found at the Citadel in this link:
Voice over and Sound Effects Specs and while they are not too specific a bit of searching in the links section will net you some more sites to check out for sound software.
Currently, my best of show, for price, functionality and ease of use in microphones is:
Sony F-V320 mic. The last time I priced it, it was like $19.00 US and it outperformed any sound card mic I have ever used, purchased or had the misfortune to try out on someone else's computer. The cord is nice and long (about 8 feet), is well shielded and the type of mic is called a Cardiod Mic, which records in a sort of heart shaped pattern with two good areas to the side of the mic to record close up (so you don't breathe right into the mic as you speak or sing) and prevents things like those Popping P's and Slushy Ssss sounds when recording.
If you can't find that one, do make sure you take the time to study up a bit. Getting one of those computer card mics with your purchase may sound cool to you, but when you record with them, it won't sound cool then. The shielding on those mics are less then stellar and you'll get computer fan hum, buzzing and tinny reproduction which will simply ruin the experience for you.
I got mine originally to plug into an amplifier to record my guitar and keyboard efforts (which, honestly, a cat's chorus probably sounds better) and have kept it all this time. I saw the same model on the shelf about 2 years ago and mine is like 15 years old, so you know it's a pretty good mic if it's still selling. It also came with a reducer plug to fit into cassette tape recorders (and it fits right into my sound card port for the microphone in the back of my computer and I can still Rock Out with all the extra cord.
Embarrasingly enough, I am actually pretty good at karaoke.

Best Buy is about the only place I know to get these nowadays. There aren't that many all in one big box stores that carry decent sound and computer gear anymore. I am sure an internet shopping search, though will yield some decent results.
Importantly: You should not have to pay more than about 30 dollars for a really decent microphone for Voice Over (VO) sound work. You can if you like, but for NWN and NWN2 purposes, the Sony F-V320 or something similar is exceptional quality, good price and great for your recording needs. Again, use a Real Microphone. Not one of those cheapo computer Skype headset things or anything else like that. They just don't have the power and shielding necessary to give a quality recording.
best regards,
dunniteowl
Edited by dunniteowl, 02 August 2010 - 09:22 PM.