Major Nelson's latest "Coming Soon" post lists Mass Effect 2's Overlord DLC with a June 15 upload date. Apparently the VI overlord is ready to go online and observe all the E3 festivities next week.
The Overlord DLC was revealed last month and will feature Cmdr. Shepard battling through "five levels set across one story on one planet" -- with a jaunty drive around in the Hammerhead tank. Entering into battle against the virtual intelligence will cost 560 ($7).
Update: June 15 date also confirmed by EA.