You'll also need a scanner with a
"transparency" or "slide"
capability. That means a back-light, typically built into the scanner
lid. Those aren't all that common, though they are becoming more
common these days.
Most of these seem to be for film strips, in fact this is the reason I've
kept my 300dpi scanner (though getting a Mac setup to use it would be
"interesting"). My new Scanner which is 1600dpi (IIRC) has transparancy,
but only for 35mm slides and film strips. With my 300dpi I can can larger
transparancies, in fact I bought it for scanning large glass slides
containing 3D pairs.
Zane