Minidisc Org - A wealth of info here
Bubblegoose - A uk based trading site (not active at present)
Minidisc Trading Post - American site but with some uk links
T-Station - Again American but lots of info on minidisc's
Md Trading - Uk based exchange site specialising in Rock and Indie Titles
Bootleg Trading Titles - specialising in bootlegs - not sure if it's uk
Miniboot - uk based trading - probably too much hassle for what it's worth!!

Mp3 Box - A comprehensive search engine for Mp3's
MusicSeek - massive directories - take a look!

HMV - Good site - Lots of album covers and track lists!!
Boxman - again good site - pretty cheap and all
Unbeatable.co.uk - good site for buying electrical hardware
BlackStar - Not bad
Jungle - Cheap cd's - only thier top 10 though
Electrical Warehouse - Very Good site - Cheapest Prices for Electrical Goods
Dabs - The best uk internet computer shop on the web - v.fast delivery