XAMPP is a quite popular Apache distribution which consists of PHP, MySQL, Filezilla, Pear and even Perl. XAMPP is very easy to install and even easier to use.
Once you finish installing XAMPP, you will see XAMPP control panel from where you need to Start the module. To open localhost, you will have to open any internet browser and type – http://localhost and to access phpMyadmin type – http://localhost/phpmyadmin
The latest XAMPP also supports Python which adds more value than WAMP. Furthermore it is extended with Tomcat server and Mercury.
You can obtain latest version of XAMPP from http://www.apachefriends.org/en/xampp.html
On the other side, WAMP is another Apache distribution consisting APACHE, PHP & MySQL. Like XAMPP, it is also much easier to install and configure WAMP.
Unlike XAMPP, in WAMP you can start all modules at once by just selecting Start All Services. The process to start localhost and PhpMyadmin is same like in XAMPP.
Installing WAMP is bit easier than XAMPP but the drawback is it comes with much less features or modules than XAMPP like Filezilla (FTP) is missing and even Tomcat, Mercury are not present in WAMP server package.
On the other hand, XAMPP occupies bit more space than WAMP. And also XAMPP is not frequently updated as WAMP.
You can obtain latest version of WAMP from http://www.wampserver.com/en/