The TI92 Hardware Hacking Homepage Some interresting stuff, as well as a temperature sensor for I2C bus.
Texas Instruments The official Texas Instruments web site, always useful for updates or info.
TICalc.org THE reference for all TI graphing calculator related software.
TI-Files Another site, has not much more than the one above
Dimension-TI Yet another, less software, but here are many hardware hacks, programming contests, ratings, etc.
Plouffes inverter It's a mathematical constant search engine : you submit any number, and it returns the nearest constant among millions !
Calculatrice de fonctions A formal calculus program on-line (french).