I've just created a free Android app which provides you with a countdown to Training Camp, the 1st Pre-season game and the 1st Regular season game. It will let you see exactly how many days/hours/minutes etc. you still have to wait until these "milestones" are reached.
The app is not just for Jags fans, as it allows you to select your favourite team, but as a long-time Jaguars fan myself, this is the perfect place to start getting the word out. Please check it out (and tell friends about it)https://play.google.com/store/apps/details?id=com.workerdroid7.nflcountdown2013