Mac users, you are cleared for departure. Set a course for the beta star system and engage, although be warned: It may get a little bumpy due to space bugs.
The Mac beta for Elite: Dangerous is now live, although currently only those who had access to the PC alpha or beta program are allowed to participate. Frontier expects to be widening the beta test in the future, however.
The team has a few specific areas on which it would like testers to focus and said that beta players will be starting with new saves and reduced-price ships.
[Source: Official forums. Thanks to Colin for the tip!]