Phono or RCA

The most common lead used to connect different audio devices

Jack

The one in the picture is mono, normally used to connect instruments. Stereo jacks are normally used for headphones.

3.5mm Jack or mini jack

Usually the sound output from a computer and most types of personal music device, mp3 players etc

XLR or cannon

male is on the left and female on the right. Used for professional audio ie. high-end camcorders, microphones etc

5 Pin-Din

Older style of audio output, found on older stereos.

Scart

Used in most consumer audio-visual devices - TVs, DVD players, VCRs etc

4 Pin Firewire or ieee 1394

used for fast transfer of data to and from computers, often for video with camcorders

6 Pin Firewire or ieee 1394

S-Video

Used for transferring video to and from different devices, provides better quality than using phono's.

USB

Used to plug almost anything into a computer!