Apple has opened the iWork for iCloud beta to everyone with an Apple ID. Previously, the beta was only open to developers and select users, but today's release means everyone get access, even those without iWork for iOS or OS X.
There are indications that iWork might go free for iOS and OS X later this year, and the fact that the iWork for iCloud beta is open to all lends support to that. However, Apple could have just chosen to open the iWork for iCloud beta to all for a limited time to test for bugs on a large scale. Apple has not issued any statement regarding the iWork for iCloud beta availability.
To access the iWork for iCloud beta, simply go to www.icloud.com and log in. You'll then see the three icons for Pages, Keynote and Numbers appear.