As of today, all users will see the Keyword Planner available in their AdWords accounts. Keyword Planner combines data from the Keyword Tool and Traffic estimator, both of which will be sunsetted in about 60 days.
Users will need to log in to their AdWords accounts to access Keyword Planner. The external version of Keyword Tool that non-AdWords users, including SEOs, could access for general keyword research will also be disappearing. The new tool is designed to make it easier for advertisers to create new campaigns and ad groups from within the planner.
To learn more about the ins and outs of the tool, Larry Kim did a thorough review of the Keyword Planner in his post, How to Use The Keyword Planner — The New Keyword Tool From Google AdWords.