Developers and committers
OpenVPN project has a large number of active developers and contributors, who are all listed in recent changelogs (2.2-beta1, 2.1.4 and later). These changelogs are available on the downloads page and in the OpenVPN release packages.
To get up-to-date information you can use some Git magic. First checkout the OpenVPN development tree as described here. Then use a command like this, provided you use GNU grep:
$ git shortlog -e --no-merges v2.2-beta1 v2.2-beta5|grep "^[[:alnum:]].*"|sort|uniq -u
The -e switch shows the email address of each contributor. To get a list of all tags (=frozen development tree states) use
$ git tag -l
If you want to contact OpenVPN developers, look here.