A simple guide that explains how to use the 0.1-incubating release of Apache Bean Validation with WebSphere Application Server V7 Feature Pack for OSGi Applications and Java Persistence API 2.0 has been posted over on the WebSphere and Java Persistence blog. While it isn't an offically supported configuration, it works very well with OpenJPA 2.0 (under the hood of the feature pack) and may help some WebSphere/EE folks get their feet wet with bean validation, especially in a JPA 2.0 EE environment.
-Jeremy