Detail about the Oracle Enterprise Pack for Eclipse (OEPE) instalation on Eclipse is published here and I repeat in the following the installation using the Update Manager of Eclipse 3.6 (Helios).
Name: OEPE Location: http://download.oracle.com/otn_software/oepe/helios (If you are using Eclipse Indigo, the Location will be: http://download.oracle.com/otn_software/oepe/indigo/ )