I'd suggest you go to a home center and have a look at their slide out cabinet shelves. When you decide what you want, wander over to hardware and select your guides.

Some other places to look for ideas, etc.:

http://shelvesthatslide.com/sliding_shelves.htm

http://www.rockler.com/hardware/drawer-slides

conversations about making drawers with the pocket-hole jig:
http://kregjig.ning.com/forum/topics/drawer-construction

Also--Unless you have a hankering to make a drawer, I think a simpler solution would be to just use a slab of plywood or regular board, if you have one big enough) as a shelf, and simply add some sort of edge all the way around.

Maybe you use something 1.5 to 3 inches wide to stand on its edge, thereby making both a covering for the plywood edge AND a lip (use wood glue and panel-board nails; but you might be best off with a good clamp--which would derail me, since I don't have a way to clamp something that large).

If you went with this, it might be awkward to use a side-mounted slide, and then you could go w/ an undermount.

The undermount would also not be visible when the shelf was not in use, though maybe the side mount wouldn't show that much either.

Hello talley_sue_nyc,
You actually had a very good idea. I think I would be able to avoid building a drawer. Not sure I can use Blum Bluemotion undermount. Their layout seems a littly "Custom"