Speaking of game designers, where do they stand in terms of amount of work completed? As all fans of Starcraft 2 know, Blizzard has released information on the Protoss and Terran while being strangely silent of the Zerg. Blizzard has stated that they have been constantly changing much of the Protoss and Terran whereas the Zerg are still in the preliminary design stages. This would indicate that Blizzard still has a lot of design work to do in the game. Similarly, one may conclude that the art for the game is in a similar stage of development.
Given this, one can see Blizzard is nearly, if not completely done with the Production stage as they move into the internal Alphas stage. With all this in consideration, it seems reasonable to say the production and alpha stages will last for another four to five months, putting the beta into April or May.
The next question becomes how long the beta will last. Looking back in time to the Warcraft 3 beta, we see Blizzard’s statement on this topic: "The exact time is not set and will depend on how long it takes for game balance to be established and bugs to be nailed out. However, judging from previous betas, the expected duration is around 3 months." The actual beta lasted around five months With that said, it seems reasonable that the Starcraft 2 beta will last three to four months. That puts the date of the end of the beta into September or October.
