For dial up users it is a pain to keep Windows XP patched and protected. To Microsoft's credit - and thanks to http://www.lockergnome.com for the head's up, you can have the patch CD sent to your home for free, bumpkis, and most importantly no cost to you.
You just visit the link below, fill out the form and in about a four to six weeks you will get the update CD to install the patches. Now whether or not you want to install the patches is a whole 'nother topic.
The short answer is yes. Back back your stuff up! Just in case.
Windows XP Service Pack 2 Update CD