The Riemann Sum program from this site should work on any TI-83, TI-83 Plus, TI-84, TI-84 Plus or TI-84 Plus CE calculator since all of them run the TI-Basic programming language. Even the new "python" models also run the original TI-Basic language in addition to the python language.
DISCLAIMER: I haven't tried this since I only own the TI-81, TI-82, TI-83, TI-84 Plus, TI-86 and TI-89 graphing calculators. But it should work.