You can use third party screen recording software (like Camtasia) for this. Not particularly cheap, but very effective. You can output the resulting recording in a variety of formats (avi, mpeg, wmv, etc. etc.), zoom in and out and have full speed control and editing facilities. It's ideal for an application such as this - I used it extensively in NATS for "real" radar/RT recordings for use in investigation and ATC training.
DC