http://microcarlover.blogspot.com/ and it's new, with very little content so far, but what it has is cool! Some photos on this site are from the Bruce Weiner Microcar Museum.
http://www.microcarmuseum.com/ with large galleries of each car, and a description of each... the museum website has Messerschmitt, Goggomobil, F. M. R. Tg-500, NSU, Zeta, Atlas, Avocette and many more.
There will even be a book on Micro trucks! http://www.veloce.co.uk/shop/products/productDetail.php?prod_id=v4175&prod_group=Cars%20Vans%20&%20Trucks&PHPSESSID=7e8c11f9d1e745ac1ceb9b633ee1d0f3
Full colour photography, text and specs describe virtually unknown production micro trucks. Featured are rare Iso utility vehicles and Topolino Fiat vans, as well as more common production micro trucks from Autobianchi, Moto Guzzi, Vespa Ape, New Map Solyto and Diahatsu. 100 colour photos show many rare and extraordinary micro trucks.