Overview: It's a big week for country music, and CMT Insider is on the scene. From Chicago to New York, our cameras catch up with country's biggest stars. Superstar Tim McGraw broke sales records with the release of his new CD Live Like You Were Dying. We'll find out exactly albums he sold his first week out and where he'll land on this week's album charts. Martina McBride made a surprise visit to Jimmy Buffet's Chicago concert over the weekend to perform ""Trip Around the Sun"" from his latest CD License to Chill. We'll give fans a front row seat for the performance and talk with Buffett about being an overnight-success country star. Hot newcomers Gretchen Wilson and Big & Rich helped announce this year's CMA award nominations live on CMT and were pleasantly surprised to hear their names read several times. We'll have a complete rundown of nominees and get reactions from the stars. In a rare interview, superstar Alan Jackson chats with CMT Insider about his upcoming CD What I Do. He'll also talk