The Apache JDO project really needs and appreciates any contributions, including documentation help, source code and feedback. Suggested changes should come in the form of source code and/or very detailed and constructive feedback.
If you're interested in committing to the project:
You'll need to fill out some legal paperwork and go through a process to get an apache committer account: See New Committers Guide, Contributors, and Committers for more details.
After you've received an email from root@apache.org with your committer account information, change your initial password: Login by 'ssh -l <username> people.apache.org'; run 'passwd'; run 'svnpasswd'. See Committer Subversion Access.
Check out the JDO sources and test your svn account: SubversionRepository.
Sign up for a WiKi account.
Sign up for an ASF JIRA account.