City of Tyler Transit Website
Route Shout - A supported web and mobile application with bus arrival times by stop. Currently using published times. Real time data to be available late Summer 2012.
Tyler On Time - An unofficial web and mobile application for keeping track of the bus schedule in Tyler. (Note: Data is currently out of date.)
WalkScore - Not Tyler-specific, but handy for assigning a "walkability score" to your neighborhood and finding amenities within walking distance.