E-book website Bilbary has done a deal with Califa, the not-for-profit co-operative of the California State library service, to offer e-book sales through the service.
Each Califa-served library will carry a 'Bilbary Kitten' button on its own website, linking to the Bilbary e-book site.
Bilbary founder Tim Coates said: "Our long-term aim is to help public and academic libraries provide e-books to their patrons and to make available the widest possible collection of e-books from all over the world. At this stage the site offers e-books for sale and soon will provide subsidised book rentals to help libraries fulfil their role."
Direct-to-customer e-book rentals are to be offered from Bilbary from this autumn.
The site currently holds 420,000 e-book titles. Random House Inc joined publishers supplying titles via www.bilbary.com as of this month.
Bilbary also has partnerships with libraries in Kansas and Denver.