Streetly Electronics are the clever chaps who make and service Mellotrons. The following are links to their main web site as well as the sample library section of their web site that I maintain for them. There are also links to two BBC radio broadcasts on the Mellotron for the uninitiated.
Link to the Streetly Electronics web site
Link to the Streetly Mellotron Tape Library
Link to a BBC Radio 4 Today broadcast on the Mellotron
Link to an extract of a BBC 'Sold on Song' episode where Sir Paul McCartney demonstrates the Mellotron