So, now that you know what SP2's going to do for you, you'll probably want to move on to the next step, which is installing the service pack before making a backup of your current Windows environment. SP2 is cumulative, so you can install it onto a fresh XP install and still have all the features provided by SP1 and other patches.
Installing the service pack is pretty simple - just run the executable and follow the prompts. It can take a while to install (the P3 1.4 GHz w/ 256MB RAM I tested SP2 on installed it in ~15 minutes), but once it's installed, you'll be asked to reboot your system. Do so, and you'll immediately notice a few changes once your computer starts up.
As you can see, Microsoft has ensured that the user has to make a conscious choice regarding Automatic Updates, which is a handy feature. After making your selection, Windows will load further and you'll be confronted with one of the major changes in SP2 - the Windows Security Centre.
The WSC is a simple management panel for your computer's security settings. You'll see the status of the Windows Firewall (default is ON), which is discussed in more detail on the next page. The WSC also displays the status of Automatic Updates and any virus protection software you might have installed. If you don't want Windows to worry about antivirus software (i.e., you've got your own antivirus installed), expand the "Virus Protection" tab and click on "Recommendations…", then check the "I have an antivirus program that I'll monitor myself" box before clicking "OK".
Before you start tweaking, it's a good idea to back up your system environment. Although SP2 does do it's own backup so that you can uninstall it afterwards, if you just want to undo any tweaks that have gone awry, this way will lessen your hassles. Do this by going to Start } Programs } Accessories } System Tools } Backup and following the prompts. This way, if XP decides it doesn't like what you've been fiddling with, you can easily restore without too many hassles.
How much to upgrade to x64 Edition?