Check out Hibernate Tools
Hibernate Tools from hibernate.org
Hibernate Tools is an entirely new toolset for Hibernate3 (see this page for an overview of the Hibernate 2.x toolset), implemented as an integrated suite of Eclipse plugins, together with a unified Ant task for integration into the build cycle. Hibernate Tools is a core component of JBoss Tools and hence also part of JBoss Developer Studio. See the documentation and screenshots for more information or download Hibernate Tools now!
The following features are available within Eclipse:
Mapping Editor: An editor for Hibernate XML mapping files, supporting auto-completion and syntax highlighting. The editor even supports semantic auto-completion for class names, property/field names, table names and column names.
-Cameron McKenzie