You may use a regular digital video camera, a web-cam or a CCTV camera.

I'm not an expert in this area, so hopefully someone more experienced will post a better solution. The following questions should help us to understand your problem better:

• What kind of video do you need (resolution, quality)?
• Do you need a fixed camera?
• Do you need a wireless camera?
• Do you want to move your camera remotely (from the same location, from distant location)?
• Do you need several people to see the problem simultaneously?
• Do you need the system to have any interaction like text chat, video chat, voice chat?