CLA
[edit] CLA is dead - Long live the OCA
Before the acquisition of MySQL AB by Sun Microsystems, MySQL used a specially crafted MySQL Contributor License Agreement (CLA) to facilitate the legal aspects of accepting code contributions from the community.
The CLA has been replaced by the more user-friendly and popular Oracle Contributor Agreement (OCA, formerly known as the Sun Contributor Agreement, SCA) Please use this agreement if you want to contribute code to the MySQL project.
You need only sign the OCA once in order to cover all changes that you might contribute to any Oracle-sponsored open-source project. If you've already signed the OCA (or SCA) in order to contribute to an Oracle-sponsored project then you do not need to sign it again in order to contribute to other projects requiring the OCA.
If you have previously signed the MySQL Contributor License Agreement (CLA), you must now sign and return the OCA instead. All contributions to the MySQL project from now on require that the contributor sign and return the OCA.
You can find information about the Oracle Contributor Agreement and general information about the contributor process in the OCA FAQ (PDF).
For more details about how to contribute code and patches to the MySQL project in particular, please check the Contributing Code page on this Wiki.