A few Apache projects have moved to Git as their main source code repository in 2012. This is still labeled as experimental, until the ASF infrastructure team is happy with the robustness and scalability of these services.
Here's the status as of mid-December 2012:
Read-only Git mirrors continue to be available.
The ASF repo must be the canonical master repo that all committers push changes to. See this document for the reasons why.
ASF releases must be cut from the canonical ASF Git repositories.
The "experimental" label on writable Git repositories should be removed soon, but infra is currently busy with CMS/svnpubsub site migrations, which will probably cause a delay of a few weeks.
Projects can request moving to Git as their main code repository, by creating an INFRA issue. See also the infra-contact page. Supplying volunteers to help infra is not required anymore
There are no plans to install anything beyond the basic Git tooling that's in place. As with svn, our infra team's plan is to to provide only basic tooling provided by the core Git developers, to ensure timely maintenance and robustness.
Custom commit or other hooks will not be supported, all projects get the same hooks. Setting up gitpubsub should provide sufficient flexiblity without impacting the core Git setup, volunteers are welcome to make that happen.