As I mentioned, the above iPhone Microscope is just one version. This one has mixed reviews. These iphone microscope adapters will essentially transform your smartphone into a microscope with one simple attachment. This is the Thumbs Up iphone microscope that attaches to the iphone 4.
The microscope produces a digital image that you can manually focus on the microscope. This particular microscope magnifies up to x100.
Some good reviews for basic use. A great gadget for some fun and taking some interesting pictures. Many other brands and types to browse through aside from just the one discussed here.
The reviews are mixed, but a couple people have mentioned that the Thumbs Up iphone microscope has fairly low quality. Read the reviews yourself and judge for yourself.