Another suggestion if you don't want to splash out on a full-blown film scanner:
there's a firm called Black Widow (www.blackwidow.co.uk) which advertises a film scanner attachment for a flat bed scanner - the FilmScan35. It's been advertised in Micro Mart and consists of a triangular block which contains an optical-grade mirror and, presumably, works by reflecting light from the scanner back down through the transparency to give you the backlighting. Costs £39+VAT. They also do a stand-alone 35mm film scanner with 1800dpi optical resolution for £119+VAT.
I don't know how significant this might be but, using your standard 1200 dpi scanner may limit the size to which you can enlarge your pictures taken on 35mm purely because of the small image size. But then again, most "professional" film scanners are about 2800dpi. I'd be interested to hear any comments on the Filmscan 35.
Now, how about one to deal with my 6cm x 9cm slides on 120 roll film?!