Newbie: b/u 2 Macs and an external drive?

[dnanian]

Well, if you want to back up three drives (2 internal, 1 FW), you'll need to create three partitions on the backup drive with Disk Utility -- you'll want to use the "GUID" partition scheme.

You'll then direct each source volume to its corresponding destination, using "Backup - all files" with Smart Update, except where you only want to do user files, in which case you'll use "Backup - user files".

You can then back up all three volumes to images on your Time Capsule -- see "Backing up over a network" in the User's Guide, and the "Airport Disks" post at the Shirt Pocket blog.