I do not have a site that gives every single gas station, but I do use the following websites to help me along the way. Each site will allow you to search for locations by state and some will even let you search by Interstate or Highway. They also all give their current diesel and gas prices at each station. That becomes handy when trying to decide if you should stop for fuel or keep going. You will know when one town is going to be cheaper than the next on your route.
www.flyingj.com
www.petrotruckstops.com
www.pilotcorp.com