Apple has started to sell iBooks Gift Cards in its retail stores. Spotted by iLounge in a Washington, D.C.-area Apple Store, the cards feature a solid color gradient background with the iBooks icon centered on top. Based on an Apple Support Discussions thread from earlier in the year, it appears as though users were able to purchase standard iTunes Gift Cards for use in the iBookstore; the new cards remove any ambiguity customers may have had about whether or not an iTunes GC would be usable in the iBookstore, and will likely be popular add-ons to those purchasing iPads as a gift.