http://www.freepascal.org/
An excellent implementation of the PASCAL programming language, and best of all, it's free. It will compile many old sources as most of the original units (libraries that is) have had free equivalents created like the DOS, CRT, etc units.
You could try Delphi, but of course, you have to purchase it from Borland:
http://www.borland.com/us/products/delphi/index.html