TI89
The TI89 tutorial is available online in English and French, the english version is the most recent of the two, the french version will not be updated anymore.
I have done a PDF version wich corrects some mistakes in the online version, is easier to see and print because I have rewritten the document in Latex.
TI89 tutorial 
TI calculators are great calculators. I use a TI89 which is one of the best graphing calculators right now. Its CAS (Computer Algebra System) is very good for a small device like that. Here are some small programs I've written. You can also find my programs at ticalc.org
Program

Description 
Screenshot 
This
program will give you your BMI as well as useful
informations 

This program will generate the Fibonacci
sequence. 

This program
will give you the Easter date given a specific year. 

This program
will try to find the extremum of a two variables function. 

This program will calculate
your Basal energy expenditure 

This program uses the Bisection method to find roots. 