Blizzard UK just announced that they are preparing to launch the Test Servers anytime soon during the upcoming days.  This is good news.

We’re happy to announce that we are now just a few days away from being able to deploy the first round of public test realms for our international audience. Due to the need to conduct as much testing of our initial Battlegrounds content as we can, the schedule calls for the next major content patch to go live on the US public test realms shortly. We will then roll out the public test realms for Korea and Europe as soon as the hardware setup and configurations are completed.

To conduct a targeted test of specific character classes for the Battlegrounds, we will be providing testers in Europe and Korea with access to a variety of high-level, fully equipped characters to choose from. More information on how players can access the test characters and the public test realms will become available as we get closer to launch. Assuming everything goes smoothly for this round of testing, we plan to deploy public-test-realm content for future patches simultaneously in Europe, Korea, and the US. We’re excited to see players from around the world on the test realms in the days ahead, and we look forward to hearing your thoughts on the new PvP Battlegrounds

UPDATE: Caydiem confirmed that Alterac Battlegrounds is meant for up to 40 vs 40 players, while future Battleground locations like Azshara and others will be for smaller groups:

While Alterac Valley is meant for 40 vs. 40, the second Battleground we’re releasing is meant for smaller, faster play… it might appeal to you.