Windows XP Service Pack 1a (SP1a) provides the latest security and reliability updates to the Windows XP family of operating systems, and includes Internet Explorer 6 SP1a. Windows XP SP1a is designed to ensure Windows XP platform compatibility with newly released software and hardware, and includes updates that resolve issues discovered by customers or by Microsoft's internal testing team. To determine whether to install Windows XP SP1a, we recommend reviewing the Windows XP documentation and information below.
If you have already installed Windows XP SP1, you do not need to Windows XP SP1a.

Express Installation Page (via Windows Update):
hxxp://www.microsoft.com/WindowsXP/pro/downloads/servicepacks/sp1/express.asp


Windows XP Service Pack 1a Information Page:
hxxp://www.microsoft.com/WindowsXP/pro/downloads/servicepacks/sp1/default.asp

Differences Between Windows XP SP1 and Windows XP SP1a.
hxxp://support.microsoft.com/?kbid=813926

Aint that some stuff, MS gets a stay on the Sun ruling and immediately they pull the VM from XP, MS will stop at nothing to make sure only their products and no one else's are installed on your machine and give you no choice in what direction you go with it.

This is a pretty quick one. Thanks for the news Fisher! Wanna check this one out. :)

I thought this is important for us to know:

To determine if you are running Windows XP SP1, right-click My Computer, and then click Properties. If "Service Pack 1" appears under System, you are already running Windows XP SP1. There is no benefit to installing SP1a if you are already running Windows XP SP1. Microsoft does not recommend that you install SP1a if you are already running SP1.

thx McoreD