For my open cup info I rely almost solely on thecup.us.
Although other sources suggest otherwise:http://espn.go.com/blog/los-angeles/soccer/post/_/id/15926/open-cup-regional-set-for-ontario
While it's possible that they might jump the gun, so to speak, My guess is that they will wait until the final slots are filled before announcing the brackets. Which would suggest a May 6th or 7th announcement.
"Bet you a beverage at the next match I'm at (probably on the 12th)" offers
That little old jersey collector
"...so different from the scenes in 1872, at the Cup Final that none of us can remember." - John Motson, former BBC TV commentator