detailed the release schedule for Firefox 5, 6 and 7. If all goes to plan, Firefox 6.0a1 will be released next week, April 12, and Firefox 7.0a1 in the middle of May. The final build of Firefox 5 should be released on June 21, exactly three months after the release of Firefox 4.
Along with the faster 6-week release cadence, Firefox's new Chrome-like release channels have also been given names and anticipated update frequencies. The most notable change is the introduction of a new alpha channel -- which is analogous to Chrome Canary -- that will be called 'aurora' and will update nightly. Aurora will be where fixes and features are tested, and either approved for Beta, or backed out to Central. Aurora will have a new icon, too.
The Nightly (mozilla-central) channel will remain unchanged in name and frequency, but it will gain a new 'nightly icon.' The Beta (mozilla-beta) channel will remain as-is, with new builds rolling out weekly. The Release (mozilla-release) channel will also remain as-is, with security and stability updates coming every 6 to 12 weeks.
It should be noted that the names (including 'aurora') are not necessarily final, but it's unlikely that they'll change. We're also awaiting the arrival of the new 'channel switching' technology, which should arrive in the next few days -- in time for the release of Firefox 6 aurora!