eWeek reports: "Computer security analysts are raising the alarm for a critical vulnerability in the Broadcom wireless driver embedded in PCs from HP, Dell, Gateway and eMachines."
This seemed like the hot topic of the day. Basically there's a stack-based buffer overflow exploit in the Broadcom BCMWL5.SYS wireless device driver. Basically if you use your Wi-Fi card to hookup to the Internet in a public place, you could theoretically have your computer taken over by this exploit.
Broadcom has released a fixed driver to its partners, but the availability of fixes appears to be limited. Check with your Wi-Fi card manufacture to find out if you're affected.