Glamour is set to produce its biggest issue in twenty years, and it's thanks to Apple's iPad.

Glamour publishing director William Wackermann told Business Insider that the September issue of his fashion title is the biggest in twenty years with 400 pages. 

Glamour publisher Condé Nast is reporting a 57 per cent increase in ad pages. That's 241 ad pages for September 2010 compared with 153 for a year earlier.

The reason for the extra pages is the iPad. Advertisers who want a space on the title's iPad app, also have to buy a space in the print edition of the magazine. The result: an increase in ad revenue for the print magazine.