Google's just announced that this year's developer conference will be May 28-29 at Moscone West in San Francisco. Registration will start at 9 a.m. Pacific time March 17 and run through 5 p.m. Pacific time March 19.
Like last year, Google says applications will be selected at random, so there shouldn't be that first-minute-and-done crush.
The schedule's a bit sparse at the moment, without even so much as a keynote address being listed, which would be a pretty major departure from previous years. On the other hand, that would put the focus back on the developers (which is where it should be, really) instead of on the dog-and-pony show (or robots and such) as keynotes tend to be. We'll have to see how that shakes out, and chances are what we're really looking at is more of a placeholder.
The conference is also a month earlier than the last couple years, so read into that what you want. Google I/O 2014 was where we got our first look at Android L (which later became Lollipop), as well as a developer preview of the latest OS.
More: Google IO 2015