If you want to get involved, please post an inquiry at the OpenMx developers' section of the OpenSEM forum. If you are interested in building OpenMx from source, take a look at the OpenMx Compilation How-To Guide. We also have a some discussion about how we use GIT. The project is licensed under the Apache License, Version 2.0.
OpenMx is licensed under the open source Apache License, Version 2.0.