FogBugz Iteration Planner
Iteration Planner helps teams construct and plan iterations from existing cases. Create milestones for backlog, sprints, doing and done — or any other structure your team or project needs. Customize each project's structure with Iteration Planner to match your ideal Agile or Scrum work flow. Iteration Planner provides the flexibility and power to make project and sprint planning work with your team.
I don’t use any of that agile process jargon. To me, it’s a nifty new view that shows multiple milestones at once, each in a column, like Trello cards. You can drag and drop to move cases between milestones. You can also create new cases and search for old ones to drag in without reloading the page.