As George has mentioned, he’ll be in California to promote HBO’s Game of Thrones. We’ve been informed that the details of the bookstore signing he noted was in the planning have now been finalized, and have now added it to our calendar. It will take place on January 9th at 5 PM Pacific Time, at Vroman’s Bookstore in Pasadena.
Also as noted in George’s post, at some point that day—not sure if it’ll be before or after the signing yet—he’ll be joining fans for a little mini-meet sort of event, just to hang out with them. If you want more details, check out this thread at the Brotherhood without Banners section of the A Song of Ice and Fire forum.