If you need a high quality capsule microphone, Marshall Electronics' MXL AC-404 USB provides excellent voice quality on conference calls at a reasonable price (about $90). If you take advantage of free or subscription Internet conferencing services such as FaceTime or Skype, it's worth a look.
The AC-404 conference mic uses boundary microphone technology and built-in custom circuitry. It has a "sports car-ish" design that boasts 180 degree coverage and a 40Hz-16Hz frequency response. It's not exactly tiny, but it's small enough that you could toss it in a bag and carry it with you when you're on the road.
The AC-404 is USB powered and will interface with Mac and Windows computers without the need for any special drivers. For the best results, you should plug it directly into your computer rather than a hub as USB hubs can interfere with the performance.
The MXL mic includes a headphone jack that works just fine with most headphones. However, the headphone volume varies by manufacturer and model, so be careful when you first plug in your headphone.
To use the AC-404 with a Mac, first plug it in, then go to Systems Preferences and click the Sound icon. To use the headphone jack on the mic as the audio output, click on the Output tab, then select the device dubbed "USB Audio Codec." You can adjust the headphone volume by moving the Output volume fader.
Next click on the Input tab and select the device named USB Audio Coded. You can adjust the volume by using the Input Volume fader. The gain if the mic is VERY sensitive. For more applications, the fader will be set toward the left.
You're now ready to go. However, some applications may require additional settings to be changed within the program.
Once you've got everything adjusted, you'll doubtless be pleased with the results. With the AC-404 plugged into your Mac you can be several feet away from it and still get pristine audio with your FaceTime and Skype calls.