The Diablo III beta is heading towards a close, as per Blizzard:
In preparation for the launch of Diablo III on Tuesday, May 15, the beta servers will be brought offline on Tuesday, May 1. At that time, all beta accounts and character information will be reset.
The Diablo III beta (publicly) began on the 20th of September last year, and has been running ever since. It will be the second-longest beta test in Blizzard’s history, being narrowly beaten by the original version of World of WarCraft, Blizzard’s sprawling MMORPG. Developer diaries on the official promotional website can be viewed to elucidate a bit on the process of making D3 on a Duke Nukem Forever-type timeline.