Software Update: iPhone, iPod Touch and iPad Update
Apple has released iOS 4.0.2 for the iPhone and iPod touch and iOS 3.2.2 for the iPad to address vulnerabilities in the FreeType and IOSurface packages. Exploitation of these vulnerabilities may allow an attacker to execute arbitrary code or gain system privileges.
This is most likely to address the jailbreakme.com website that was able to jailbreak these devices through a website.
Links for More Information:
iPod Touch/iPhone: http://support.apple.com/kb/HT4291