For members updating to SP3, here are a few helpful links:

Overview of Windows XP Service Pack 3
"Includes all previously released updates for the operating system, in addition to a small number of new functionalities that will not significantly change customers’ experience with the operating system."
Release notes for Windows XP Service Pack 3
More Release notes for Windows XP Service Pack 3
(addresses late-breaking issues and information about: IE7, RMS, MUI, Scripting, Remote Desktop Client 6.1, XP Media Center Edition 2002)

Installing Windows XP Service Pack 3
"The computer must be running Windows XP with Service Pack 1 installed. Microsoft recommends that you have Service Pack 2 installed before installing SP3."
Steps to take before you install Windows XP Service Pack 3- Troubleshooting SP3 installation
Minimizing XP SP3 woes - Updated
Windows XP SP3 - What You Need to Know: New Features

SP3 Download links:
Windows XP Service Pack 3 Network Installation Package for IT Professionals and Developers
Windows XP Service Pack 3 - ISO-9660 CD Image.

NOTE: Currently there is no SP3 update for Windows XP (x64) because the kernel is based on Windows Server 2003 (x64) which has a separate update time-line.
---------------------------------------------------
XP SP3 CDs available from Microsoft:

SP3 CDs cost $3.99 plus $5.99 shipping. They are currently on back order but should be ready for mailing in early June.

Call MSFT at 1-800-360-7561 and choose option 2 to Place an Order.
Next chose option 1 to Place Order for a Service Pack.

A representative will take your order and billing/shipping information.

---------------------------------------------------
Important Notes! XP SP3 cripples some PCs with endless reboots - (HP/Compaq with an AMD (non INTEL) processor systems)

• Jesper's Blog: Does your AMD-based computer boot after installing XP SP3?
NOTE: The May 14th update to the above link includes a small tool written by Microsoft MVP Jesper Johansson that will detect the IntelPPM problem and mitigate it before installing the service pack.

• HP has posted a work around with instructions to boot into Safe Mode and disable the Intel Power Management. See HP Pavilion and Compaq Presario Desktop PCs - Computer Restarts after Displaying Stop Error 0x0000007E (After Updating with SP3)

• HP also released a patch for AMD based systems: Microsoft Windows XP SP3 Upgrade Utility for systems with AMD processors.

• Symantec urges caution before SP3 upgrade.

---------------------------------------------------
** Need Help and Support from Microsoft?
In North America, free telephone support is available by calling (866) 234-6020 (support is available for Service Pack 3 until April 14, 2009).
Or click here for free E-mail or Chat Support.

Windows Service Pack Blocker Tool Kit

_________________
"THE BAD GUYS DON'T NEED A SEARCH WARRANT. ARE YOU PROTECTED?"

Microsoft MVP - Windows Security 2007-2008