First, I showed all those http://www.youtube.com videos on programming the TI-83/84.
Then, I installed VTI on my Fedora 11 CD clients using wine.
So, we wrote some simple IPO (input, process, output) programs (eg: input 3 sides of a triangle a,b,c and process the area with heron's formula and output the answer).
We also wrote some looping apps (ie: enter a number of grades to average).
Finally, we wrote a quadratic equation solver that used conditional statements to output the nature of the roots as well as the roots themselves in a+bi form.
For a week and half final project for a semester intro course, I think it went quite well.
BTW, I misspoke in my last posting on this subject. I said there were a number of good sample programming videos on youtube for the TI-83/84. I also said, mistakenly, that there were no such good videos for the TI-89. Well, see the video for yourself as its embedded above. I don't know how I missed it as its one of my own recordings!
Teaching with Technology,