You can just pile leaves in a heap or composter and turn occasionally and you get leaf mould or you can alternate it with horse manure and make compost.

Spritzhenry has a good blog on this, done a while back now, called Black Gold, its a good guide as to how to make it. See if you can find it by going to her profile page, selecting her 'blogs' and scroll down for the right one. It involves black binliners full of leaves, left for a year or two to rot down...

Compost needs heat but leaf mould needs cold to work but not wet. I have a leaf hoover which chops them up quite small and I put in old string potato bags and black bin bags with lots of holes and stack them in a shaded part of my garden under large shrubs and in 8-10 months I have great results.

Thanks very much everyone, very informative, ive had a quick look at spritzhenry's blogs and theres so many i didnt have time to go through them all but i did have a rough idea and now my mind is at rest....big thanks again. ;-)