Before You Buy a Webcam
Webcams are not unlike computers -- there is a tremendous amount of models available, with prices ranging from the extremely affordable to the very high end. Since you don't want to pay for features you'll never use, it's a good idea to nail down exactly what you need and what you don't.
What You Definitely Need
A webcam with a high resolution is imperative -- the lower the resolution, the grainier your image will appear on other's screens. A decent resolution starting point is 640 x 480.
Likewise, a high frame rate is crucial. Webcams without high frame rates produce images that stutter and periodically freeze on the viewer's screen. Frame rates are measured in frames per second, so look for "fps" on the webcam packaging. You must stay above 15 fps in order to stream video, and you're better off staying closer to 30 and higher.
What You Should Get
The type of lens will affect the webcam's performance. Some entry-level webcams feature plastic lenses, but it's wiser to stick with a glass lens since they dramatically improve performance without significantly raising the price.
Auto-focusing and automatic light-adjustment technologies are useful in webcams, especially if you'll be using it in a darkened room (e.g., a bedroom for video chatting).
A built-in microphone and the ability to take still images are increasingly becoming standard features. Look for a webcam that can take images that are at least 2.0 megapixels.
How to Disable a Webcam
Bells and Whistles
Motion sensing can turn your webcam into a veritable security system, and some models come with this feature built into it. If yours does not, don't fret - you can download software instead.
Depending on the type of video chatting you do, you may want to include special or video effects, and many webcams come packaged with these abilities. But, as with motion sensing, you can also download special-effects software if yours does not.
Weird, Strange and Cool Webcam Feeds
The ability to capture high-definition video is now a popular feature in webcams. If you plan to frequently stream video to social-networking sites, this technology may be for you. But note that high-def recording will most certainly drive up the price of the webcam, so feel free to skip it if you just want a webcam for video chatting. High-definition refers to a model that captures 720p video or higher.
Webcam prices range from the extremely affordable (Micro Innovations has one for $9.97 on Amazon.com) to the high end (the WoWee Robotic model on ToysRUs.com for $299). You tend to pay for what you get, so be sure to weigh your feature needs and budget needs carefully.