Programming requires special tools to convert your written program to the technical language that your computer understands. Depending on the programming language, you need either a compiler or an interpreter to operate the computer. These Web sites have the tools for common languages.

Visual Basic, Visual C#, Visual C++, Visual Web Developer tools (www.microsoft.com/express) (Windows only)

Turbo Delphi, Turbo C++, Turbo C# compilers (www.turboexplorer.com) (Windows only)

REALbasic (www.realbasic.com) (Windows, Mac OS X, Linux)

Runtime Revolution (www.runrev.com) (Windows, Mac OS X, Linux)

Ruby (www.ruby-lang.org) (Windows, Mac OS X, Linux)

Java (www.java.com), (Windows, Mac OS X, Linux)

Python (www.python.org) (Windows, Mac OS X, Linux)

Perl (www.perl.org) (Windows, Mac OS X, Linux)

PHP (www.php.net) (Windows, Mac OS X, Linux)

GNU Compiler Collection (http://gcc.gnu.org) (Windows, Mac OS X, Linux)

Dev-C++ and Dev-Pascal (www.bloodshed.net) (Windows only)

Free Pascal (www.freepascal.org) (Windows, Mac OS X, Linux)

NSBasic (www.nsbasic.com) (Windows, Palm, Symbian OS)

SWI-Prolog (www.swi-prolog.org) (Windows, Mac OS X, Linux)

CLISP (http://clisp.cons.org) (Windows, Mac OS X, Linux)