Nine months ago we moved all of OLX to Jira (http://www.atlassian.com/software/jira/). We are extremely satisfied with the product.
It’s extremely important to input every single project your tech team is working on. If you don’t document very small bug fixes and changes, you can end up having a large portion of your tech resources on projects that may or may not be very important.
Also note that online project management tools like Jira and Trac (http://trac.edgewall.org/) are much more useful than PC based solutions. Everyone always sees the latest version of all the projects. Developers assigned to a project can comment on it or update the status in real time. Managers can update specs and track their projects.
There are many ways to organize your release schedule to fit your organizational needs. At OLX, releases are on an ad hoc schedule, but we average a release every 2 weeks. We also have a weekly product meeting where we cover what was released, upcoming releases and adapt project priorities as needed.