Blacklight: Retribution will launch its beta tests in late October and early November, right in the midst of shooter season. Publisher Perfect World Entertainment announced the dates today, starting with Phase 1 on October 27, followed by Phase 2 on November 10.
The Blacklight: Retribution site outlines the closed beta roll-out, which will be by invitation only. Phase 1 starts on October 27 and ends on October 30. Phase 2 begins November 10 and ends November 13. In both cases, the servers will be shut down after the end date, so you'll have to get your playing in while you can.
Perfect World implies that more phases are coming, so if you don't make the first two waves don't fret. If you haven't already, you can still register for the beta. The beta will wipe player data several times, so when the free-to-play game launches its full version, everyone will be on equal footing.