Download the apachesolr module from drupal.org, and put it in sites/all/modules:
http://drupal.org/project/apachesolr
download solr-php-client, version 22
http://code.google.com/p/solr-php-client/downloads/list
and uncompress it in the apachesolr module directory.
Ready to activate the module, but we will did not installed the Apache server, so the module will not work.
Now, as you guessed, it's time to install the apache solr server. Download one of the latests releases:
http://www.apache.org/dyn/closer.cgi/lucene/solr/
Remember to download the binary files, not the src directory. You'll know that you have the correct tar if you have an example directory with a .jar file.
Now, time to move all these files to a .bak version in conf directory
apache-solr-4.0.0/example/solr/collection1/conf
- schema.xml,
- solrconfig.xml,
- protwords.xml
then, copy these files from your drupal module directory.