At the Microsoft Management Summit 2008 in Las Vegas an announcement was made on the proposed release of Opsmgr interop connectors for IBM Tivoli Enterprise Console and HP OpenView for Windows and UNIX. These are currently in beta and may be downloaded from the Microsoft Connect site.
Details can be found on the System Center Team Blog
You can download the Cross Platform Extensions Beta through Microsoft Connect. To help you navigate to the right spot, follow these directions: