Articles: We uploaded Cross Platform Management Packs at MPWiki! Enjoy the information: http://scommanagementpackwiki.viacode.com/default.aspx?g=posts&t=41755
Articles: Article avaialble as a download in this post. It is in .docx format.
Articles: Monitoring FreeBSD from SCOM.
Articles: by Robert Hearn[MSFT], this 3 part series includes everything you need to monitor CentOS with XPlat feature of Operations Manager 2007 R2.