Sure, it won't get you live 3D representations
of living cells, but this little USB microscope
mashup over at Instructables should nab you some sweet pics of up-close detail with a minimum of effort. You can pull it off with basically any simple webcam -- the one pictured here cost $5 -- and toy microscope, but you'll have to a little creative wiresplicing to get the white LED light source powered off USB as well. Still, it's a neat project if you've got the time -- now get to work!