Before you do this get a copy of something like Partition Magic if you don’t get it just right. I did this before I finally upgraded to Vista and frankly, I didn’t want to be bothered with all the aggravation. Ubuntu can be downloaded and it is easy enough, but the bootup menu can be troublesome and may lock up your computer as it did mine. I finally got a work around off the internet which I installed but the truth is that I didn’t see the point of it. As I understand it only about 1% of the PC population uses Linux.
Good luck. You will need it.
For someone just getting their feet wet with Linux, you can’t go wrong with Ubuntu. The nice thing is that you can try it out as a “Live CD” before you install it on a HD partition. If I were you, I would go download a Ubuntu ISO right away and start playing with it. If you are happy with it, then there’s an icon on the desktop that will allow you to install it to a partition.
I concur that working directly from a CD is the most foolproof way to try out the system. Of course the obvious downside is that is much slower than working off the hard drive. I guess you might install it on a flash drive if it will boot from it but that is beyond my expertise. Ubuntu can also be ordered free and I received three copies of it in about two or three weeks if you don’t want to download it from the internet.
Boot from the live-cd. It will fire up Ubuntu and let you take it for a test drive without installing anything on your system. From the desktop you can start up the installer which will walk you through setting up a dual boot system, including the partitioning.
Obviously, as with any such endeavor, back up your important data first, etc, etc.
I haven't used anything MS at home in 3 years and I haven't missed it or the anti-virus or anti-spyware, either. It isn't as difficult as those who have tried and failed would have you believe.
Once done, I would recommend SimplyMepis as the Linux choice. I've done dual boot with Ubuntu also. I like SimplyMepis better. It handled my wireless interface flawlessly where Ubuntu had to tweaked, prodded and cajoled.
The best website I found for a step by step guide is here:
Creating a Dual-Boot Windows XP and Ubuntu Laptop
It's for Ubuntu but can be used for other distros.
Good luck!
I would use Fedora Core, its Redhat’s free version with live update support.
Install Fedora first and leave a partition for the Windows install. I use this setup often. Good mix.
Mint Linux: Ubuntu plus extras for a better out of the box experience
OpenSUSE: Best post-install support of hardware
Sabayon Linux: Cutting edge experience see here
But keep in mind, whether CD or DVD, it is slower than a HD. And a few other limitations of running from a RO partition. So don't let that keep you away.
If you do decide to install on HD, then a dual boot is fairly straightforward. You'll get a choice of boot loaders. I use Grub myself. And while I haven't used it with XP, it worked with W2K without a hitch. Whatever Windows boot menu you have (if any) will be replaced with the Grub one, which will list XP as an option.
One more note. If you're comfortable working with partitions, you might want to make your /home directory on another slice. This way, you can keep your personal data off the system partition. This may or may not be done by your particular distro. But I've found it helps if the system slice gets trashed for whatever reason. You can recreate the system and it will see your existing /home and use it. No data loss.
Of course if you're not comfortable working with partitions, then forget that last paragraph.