Here is instruction provided by Tony at Drupal for Windows with XAMPP installed:
Preliminaries
- Make yourself a nice cup of tea
- Make sure you have the Windows Java environment installed. It's up to version 6 at the moment.
- I assume you use XAMPP to run Apache and MySQL and latest version of PHP5
Installing Tomcat
- If you installed XAMPP with Tomcat, go to your Service Tray, stop XAMPP services and remove the Tomcal directory from within your XAMPP installation. Then restart your XAMPP again. The reason is that you want to be able to configure Tomcat easily from Services Tray in Windows. If Tomcat runs under XAMPP, it does not show up in the Services Tray.
- Before you install Tomcat, copy the file c:\windows\microsoft.net\framework\v1.1.4322\msvcr71.dll to c:\windows\system32\msvcr71.dll If you don't do this, Tomcat won't start up.
- Now install Tomcat 6.x. Start it running. You should get a page showing at http://localhost:8080 if Tomcat is working.
- Have a peek at the file structure of Tomcat. It is very straightforward. Note the directory called webapps.
- Now have a nice cup of tea.
If you're on Linux, check: Apache Solr 4.6.0 installation.