wanted: digital camera for microscopes

We have several microscopes and we would like to capture digital images of what we see–especially pollen grains. Which on should we pick? Any advice would be appreciated. Here are some links to pages about several models of inexpensive USB cameras that can mount to a microscope:

microsope.com sells several brand. They sell only one line from bigC.

Here’s a company that sells the EM series from bigC.

documentation pages on the bigC product line (more on the AM series than the EM series).

Another source of info on the Moticam line.

I scanned this list of companies that sell (and used to sell) microscope accessories to find the above links.

FYI I stumbled across some pollen identification keys: a taxonomic list, a key to pollen of the bahamas, and an inaccessible “pollen database” that sounds good.