I've migrated the IntelliJad plugin for use in IntellJ IDEA 8. You can find the details at http://plugins.intellij.net/plugin/?id=2665
There is one issue that I have found - when you open a Java class through IntelliJad, the focus does not shift to its editor; instead, it remains with the previously selected editor. I've already posted about this in the EAP forum and will fix it when I have the answer or the openapi is patched.
Any problems, question, etc...let me know.