Here is a small list of the different types of connectors that are normally used on a computer:

BNC Connector

BNC connectors are generally used on Network Cards with a male BNC end on the card.

RCA Connector

RCA connectors are used for audio and video connections from some sound cards and TV cards. The general convention is that yellow is for video and red/white is for audio.

F- Connector (Coaxial)

F-connectors are generally used on TV cards to feed a cable or antenna feed to the card. It is the used on coaxial cables.

S-Video

S-video connections are also found genrally on graphics and TV cards. Some sound cards also come with S-video connection capability.

1/4 Jack

The 1/4 Jack (or connector) is usually for audio and can be mono or stereo. You would not generally find a 1/4 connection on a computer. You would have to use a 1/4 to 1/8 converter if you wish to connect it to your computer.

1/8 Jack

The 1/8 Jack (connector) is generally plugged into the microphone, auxillary audio (in), and speaker ports. Again, colour convention applies: green - auxillary audio (in), orange/pink - microphone, purple - audio out.