Tracking Agile Projects is about monitoring the project health, and checking adherence to the schedule is a relatively simple exercise. The amount of work actually completed in an iteration is compared with the amount of work expected to be completed. Differentials are feed back into the amount of work expected to be completed in the future iterations, which has a self corrected effect on the project schedule.
Agile Planning and Estimating covers the activities involved in actually planning how the software being developed is going to be built, splitting up the development into manageable pieces and deciding a schedule for the release. This part of my Agile development guide is based on the excellent book by Mike Cohn, Agile Estimating and Planning.