I am using Geoserver 2.2.5 & added 'geoserver-2.2.5-oracle-plugin.zip' at '..\geoserver 2.2.5\webapps\geoserver\WEB-INF\lib' to connect with oracle data.
after restarting Geoserver, No datastore like 'Oracle/Oracle NG' is found.
The two jar files(in 'lib' directory) are -
1) ojdbc.jar ;
kindly,note that in the same process I installed 'MySql'Plugin & it is working fine.
Thanks in advance