Because of the tremendous growth of the Internet there are many, many places where you can find calculator programs. My suggestion would be first to look at ticalc.org because they have the biggest archive for all TI calculators. They have a lot of TI-83 and TI-83 Plus. If you're looking for a specific type of program, it most likely will be there. If it so happens that you don't find what you are looking for a TI-Calc, then try Dimension TI. Dimension TI is the major rival of TI-Calc. They too are pretty big, not as big as TI-Calc. They usually, however, have the same programs as TI-Calc becuase most programmers submit to both sites. If you still do not find the program you're looking for (this is highly unlikely), then try searching for TI-83 or TI-83 Plus programs using one of the major search engines like Yahoo! or AOL.com Search. You'll most likely receive a lot of sites to choose from. If it so happens that you still cannot find the program you're looking for (you gotta tell me if this happens), make the program yourself. You're obviously the only one who needs this type of program. If you need any help making it, just ask.