First, for people still using Windows XP, Service Pack 3 has been released to manufacturing (RTM). SP3 is expected to be available on Windows Update on April 29.
See TechNet, Windows XP Service Pack 3 Released to Manufacturing.
The next bit of news is that Microsoft has released the latest Microsoft Security Intelligence Report (SIR). As reported at Microsoft Press Pass,
"The report focuses on the second half of 2007 and uses data derived from a range of tools running on approximately 450 million computers worldwide to provide an in-depth, global view of software vulnerabilities, software exploits, malicious software and potentially unwanted software.A complete report and copy of the SIR is available from the Microsoft Malware Protection Center.
The latest SIR shows the fewest number of security vulnerability disclosures across the software industry since the second half of 2005, along with a rise in malicious and potentially unwanted software, which demonstrates a continued use of malware as a tool for targeting computer users for profit."