While perusing the R.A.MP.S. boards the other day, I found a link to what appears to be the online catalog of mics.
Sponsored by Rycote, microphone-data.com is an exhaustive reference site for pretty much anything you'd want to know about professional microphones, including pictures.
Microphone Data deals in facts, not opinions, with pictures, response curves and technical data from the manufacturers themselves for every currently listed microphone (and even a few that aren't).
To put the data into context you will also find a library of articles by some of the most eminent people within the audio industry that Rycote has commissioned specially.
Link to website.