Google I/O, the search giant's annual conference for developers akin to Apple's WWDC, is due this year May 28-29 in San Francisco's Moscone Center West.
Sundar Pichai, Google's Vice President of Android, Chrome and Google Apps, announced in a post over at Google+ that registration will open on March 17, 2015 at 9am PDT.
A Google account is required to apply for your seat and only one registration application per person is allowed. However, there's no need to rush because you'll have plenty of time to submit your registration application.