The TI-89 manual contains all of the information that you will need to program TI-89 BASIC, and if you have specific questions, you can post them on the TI-89 Forum and someone will probably reply to them. For TI-89 68k Assembly programming, Techno-Plaza, has some introductory lessons, and if you know some assembly already, Jimmy Mardell's 68k Guide is a really good reference. For programming C, there are many references and if you go to your local bookstore, there should be some good tutorial books for it on the shelf. You should also be able to find some on the web through search engines. Also, the programming group TICT has some C programming demos, and TI-GCC is the best C compiler for the TI-89 at the moment. Texas Instruments also provides a TI-89/TI-92 Plus SDK for developing Flash APPS in C or Assembly, but it is currently in early beta (as of Spring 2002) and not many people are using it.