The Sonoma-Loeb company offers a historical view of the corkscrew.
Article describing corkscrew collecting with examples and leads to other information.
All about corkscrew collecting, the how to do it page.
A nice educational piece on the Henshall button type, Thomason and multi-tool harp corkscrews.
A news story on Champagne lovers, has some corkscrew information as well.