This poster is a mashup of three of my favorite things: reading, vintage posters and foxes! When I saw it on Steph's blog I had to know where it was from. I found it and three others like it for sale and I'm happy to tell you where:
You can find them for sale (no need to go through an auction) at eBay store Cervi-Roche Auctions for about ten dollars. They're pretty big - you can see how one looks all nice and framed at Steph's house on her blog Simply Radiant.