[dnanian]

You'll want to partition if you can, certainly if you want to store things other that just an SD! backup alongside Time Machine.

There are a number of good Leopard books out there (e.g. the Missing Manual series), but if you'd like a quick "partitioning" step-by-step:

* Start Disk Utility
* Select the external drive hardware in the sidebar
* Click the Partition tab
* Use the UI to create the number of partitions you want. Use "Mac OS Extended (Journaled)" as the format type and name appropriately
* Click Options
* Choose the proper partition scheme (GUID for Intel macs, Apple Partition Map for Power PC) and accept the page
* Click Partition.