On Instructables, Yoshinok explains a clever, simple method for building a digital microscope stand that uses your phonecam, focused by a laser-pointer lens.
This instructable will show you how to build a stand for about $10 that will transform your smartphone into a powerful digital microscope. This DIY conversion stand is more than capable of functioning in an actual laboratory setting. With magnification levels as high as 175x, plant cells and their nuclei are easily observed! In addition to allowing the observation of cells, this setup also produces stunning macro photography.
$10 Smartphone to digital microscope conversion
(via Red Ferret)