I use a mic often using Teamspeak and I usually have no problems doing it. Also , using the mic under the "test microphone" thingy seems to work too.

But when I get into the game itself and go to use the microphone, no one can hear me. On the test microphone it seems like its lound enough *shrug*. The little yellow sign with an exlamation mark pops up in the bottom right corner but still no one hears me.

any thoughts?

Is mic boost on in windows?

If not, go to your volume control panel, make sure the "microphone" bit is there (if not, select it in Options). Select Options > Advanced Controls. Click on the "advanced button that should be under the microphone scrolly thing and tick the boxes

You could try using voice_loop 1 in NS to see what other people hear.