It looks like Anthony Horowitz will not be doing a U.S. book tour for Trigger Mortis as originally planned. This is disappointing news, and it's going to make finding signed copies of the U.S. hardcover from Harper Collins a trick for collectors.
U.S. tours have become a rare thing for Bond authors these days. Only Charlie Higson and Jeffery Deaver have brought their Bonds to the U.S. in recent years. Horowitz had listed a section for "U.S. Events" on his official website, but that is now gone.
Horowitz will be doing a tour of the UK. You can check out the schedule here. Trigger Mortis will be released on September 8, 2015 in both the U.S. and UK.