Hi Greg,
You also have another choice available, use a LiveCD.
You place the CD into the tray, and reboot PC. The OS will be placed into RAM, never writing anything onto you HDDs.

Some, (Knoppix, Kanotix, and other versions based on Knoppix), offer no easy install options. It can be done, but for a Linux newbie, forget it. These versions are designed for PC diagnostics, but with a thumbdrive (>500Ms), you can save personal settings from your sessions.

Others, PCLinuxOS, SimplyMEPIS; offer easy installations. You didn't state if you're going use entire disk for Linux, so I'll offer you a suggestion. Don't.

When you go through the install, key points to remember.
Choose custom install, set up partitions yourself. You'll get a partitioning window, choose HDB, HDA has your XP.
Click the bar representing drive, create 75Gs as ext3. Don't worry about naming it, choose default.
Create 1G as linux swap, then 100G as ext3. Create remainder as windows, this is good place for you to use as a Windows backup space. Now partition table will be written, leave CD in tray, and reboot.

Go back through the install, now you going name the partitions.
First one is "/", this your root directory. Also included in this directory are; /usr, /opt, /temp, and /var. Programs and log files are stored here.
Next (green bar) is "/swap", after that, "/home". This is where you'll live when running Linux, all of what you do, will be stored here. It's not necessary to name the windows part. Continue with the install.

Choose a password for root. You don't need to be reminded about password security, right?
Choose users, if yourself, your almost done.  Install moves along, then you get to part of the boot manager.
Highlight 'windows', modify. Make sure it's pointed to boot off at HDA, from what your stated specs lead me to. Mostly, the setting you see, should be correct. Linux won't complain about Windows, unlike the other way around. You may have noticed an "*", this is the default boot OS. This is the time to decide which, and how many seconds, before making choice automatically.

Linux desktop closely resembles Windows, that the start button is at the bottom left.
Shut down, reboot. If you got a friendly LiveCD, disk should eject before total reboot. If not, be ready during BIOS check to eject disk.

The next time you go back into Windows, 'My Computer' will show you have a new drive. Format, then point your backup program to save here. 

Do check out www.tldp.org. In order to use Linux well, requires reading.

Don't EVER run as root, always as an user.

Good Luck with the penguin on your shoulder,
Timothy

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