Might be a little over-kill and/or not as easy to operate, but there is a TI calculator emulator. I've used the TI-89 all through high school and college so it was very handy and easy to use with exactly all the same functionality as a TI-89.
You can also emaulate the TI-82, TI-83, TI-83 Plus, TI-85, TI-86, TI-89, TI-92, TI-92 II, and/or TI-92 Plus calculators.
http://62.65.69.4/archives/files/fil...309/30978.html
The setup is kind of large (~2 MB I think) + the ROM OS (~1.2 MB), but you can remove the extra skin files that you aren't using to get the install back to ~1.8 MB.
Edit:
See the link below for the TI calc ROMs:
http://<br />
http://www.ticalc.org...s/romdump.html