I have been asked this question a few times now, so thought I would blog the answer.
How do I create a capture CD (Capture Media) in Systems Center Configuration Manager 2007
Under Operating System Deployment. Right click on Task Sequence and choose "Create Task Sequence Media".
In the wizard you have three choices.
1. Stand-alone media 2. Bootable media 3. Capture media
Good tip Dave, more info on this subject here