The deal gives Facebook's users a six-month subscription to McAfee's Internet Security Suite, followed by a special discount. This gives them access to antivirus and anti-spyware protection, and also includes SiteAdvisor, McAfee's website rating service.
Facebook will also be using custom security software developed by McAfee to help clean users' computers in the event that their accounts are compromised.
The two companies will also be developing educational content for the security part of Facebook's website, and McAfee will also update its own page on Facebook's service with regular news and advice.
The announcement comes just a few weeks after McAfee predicted that Facebook would be among the top targets for black hats in 2010.
Facebook needs all the help it can get on the malware front. The Koobface malware strain has been spreading widely using Facebook. In October, security companies began detecting malware that created false accounts, bypassing the Facebook captcha and luring users to click on fake video links. Most recently, a false Facebook group telling users that they will be charged for their Facebook accounts this year was used to serve up scripts that hijacked users' computers.