Butterflies of America – Odd name as the site covers all of North and South America. Lots of good photos.
The Moth Photographers Group – Hosted at Mississippi State University, has pictures, distribution maps and adult flight times for just about every moth found in North America. A fantastic resource!
Western Canadian Lepidoptera Info
Norbert Kondla’s Butterfly Pics on flickr – Great pictures, very useful for ID comparisons.
Lepidoptera Societies and Associations
Equipment and Supplies
Bioquip – US Supplier of just about everything entomology related.
Atelier Jean Paquet – Quebec based supplier.
Watkins & Doncaster – British entomology equipment supplier since 1847!