ticalc.org - One of the most informative and in depth sites about TI graphing calculators. Includes tutorials, columns, news articles, and the biggest file archive out there.
Texas Instruments - TI's calculator division and the official site about TI calculators. Includes information about calculator models, computer linking software, and some math applications.
TI-CAS - Contains math and science programs as well as tutorials for the TI-89, TI-92, and TI-92+, with a focus on learning and on computer algebra systems.
calc.org - A large TI calculator site with news updates, information on programming, a program archive, and link cable and hardware information.
Texas Instruments' FTP Site - TI's FTP site, containing Graph Link software, math and science programs, CBL applications, and a few games.
Shiar's TI Calculator Page - Games and programs with screenshots and descriptions for the TI-83, TI-85, and TI-86, along with polar graphing information.
The Richfiles - A TI-Basic tutorial and information about calculator pricing, acceleration, creating a backlight, and power expansion.
TI Graphing Calculator FAQ - Responds to common questions seen in discussion groups, and contains additional useful information about things that can be done with a calculator.
TI-Net - Site with frequent news postings about TI calculators, including information about new games and programs.
Sami Khawam's Homepage - A general TI site with an emphasis on hardware, including linking software, infrared linking information, and a memory expander.
TI-8x Programming - Games and programs with descriptions and programming tutorials for the TI-82, TI-83, TI-85, and TI-86.
Endeavor - Categorized directory of software, links, articles, and tutorials for TI calculators.
TI Acceleration Pages - Contains extensive information about TI calculator hardware, especially regarding overclocking TI's, a potentially risky process that can make them run faster.
Roberto Perez-Franco's Symbulator - Includes engineering and math programs for the TI-89, TI-92, and TI-92+, including a symbolic circuit simulator.
TI Calculator Help Center - Contains instructions and programs for using the TI-82 and TI-85 graphing calculators for Algebra courses.
Statistical Inference on the TI - Problems and solutions about statistics for TI's, intended to supplement a general descriptive statistics course.
Flash Website - Original assembly programs for the TI-89, TI-92, and TI-92+, including source code and screenshots, as well as a few other programs corrected to run with HW2 and AMS 2.0x.
TI59 Programmable Calculator Hardware - TI59/TI58 hardware descriptions and diagrams.
opensource.calc.org - Information about all things open source in the TI community, with documents, a message board, and viewable code.
C2 Coding - Contains programs for the TI-83+, TI-85, and TI-89, with tutorials, programming contests, and links.
TI-Tiplist - Tips, tricks and examples of usage for the TI-89, TI-92, and TI-92+. Extremely extensive and informative.
Yarin's Homepage - Original programs for the TI-85, TI-86, and TI-92, as well as assembly programming tutorials.
TeZXas - ZX Spectrum emulator for the TI-89 and TI-92+.