LAMP (Linux, Apache, MySQL, and PHP/Perl/Python) is a complete open source Web development platform that is an alternative to commercial solutions such as Microsoft .NET, Oracle WebLogic, and IBM WebSphere.
Most companies are already using some element of LAMP. For example, Netcraft reports that Apache is the number one Web Server software. Similarly, it is possible to have a solution stack of Apache, MySQL and PHP/Perl/Python on a Windows platform (referred to as WAMP).