Redmond wants you to move away from XP.  XP has been around for 10 years. Windows 7 seems on track to take XP?s place as the most-used OS.  The Net Applications site shows that XP still holds 47.29% of the market, with Win7 next with 30.36%.

Redmond really wants XP to leave, for instance IE9, which is more secure,  will not run on XP. Their Download Center even offers a little WinXP "End of Support Countdown Gadget", ticking off the days until XP's official support ends in 2014.  There are less than 893 days left.
http://www.microsoft.com/download/en/details.aspx?id=11662

If your computer has Windows Vista, and only have up to Service Pack 1 installed, Microsoft has a message for you:
Upgrade to ServicePak 2 or? buy Windows 7.
The official date for the transition is July 12, 2011. After said date, users will no longer have access to security updates or patches from Microsoft - which would leave the computer vulnerable.

No, you don't want to migrate from XP to Windows 7 - because the Video drivers, Mouse driver, Keyboard driver, sound drivers are all 16-bit or 32-bit software, not the 64-bit software required for Windows 7.
Did you know that if you copied the DLL's for Outlook Express, that Windows 7 will not run Outlook Express?
Windows 7 can run Windows XP inside a window, true, but that will require 4 GB of memory or more.  Many of the older motherboards can only handle a max of 2 GB... so pull out your motherboard book first and check.

My suggestion is to let your 32-bit operating system alone until someday when you finally replace the computer.  If you have a Dual-Processor computer, you can continue running XP very nicely until July 2015. 
If your XP is running slow, chances are it just needs to be cleaned-out and optimized. 

1USA Customers get access to FREE software to keep your XP in tune.  There is NO need to spend $50 or more for software.  A 1USA subscription is as little as $60 if you already have a broadband connection!
If you have a hole burning in your pocketbook to install Windows 7, the tutorial is here.

If you're one of the many people who are still running XP with ServicePak 2, be aware that Microsoft plans to cut off support for that iteration next summer. You'll need to goto http://windowsupdate.microsoft.com and upgrade to ServicePak 3 in order to continue to get WindowsUpdates. 
To check your computer, goto Control Panel > Add-Remove Programs.  Click on the checkbox at the top to display updates.  ServicePak 3 for XP should be near the bottom of the list.
Extended support with ServicePak 3 will continue until April 2014.

Support for Windows 2000, should you still have any computers running that operating system, will also end in July 2010.

When the government quotes sources, are the sources slanted.  Details at TheRegister.