As of today, anyone running a mozilla-central nightly build (all zero of you) will start receiving nightly updates for it. There isn't a whole lot going on there right now but this is another step is getting 1.9 parity on Mozilla2. Many many thanks to nthomas for teaching me so much about the update system while getting this going. At some point in the future we plan to enable updates for other branches as well, such as actionmonkey.