Helpdesk type functionality

i have been checking out the work item stuff in tfs and it does cover bugs and pre-live situations well, but is there any out of the box functionality that covers issues in a live environment? i.e. helpdesk-like functionality

or are any of the partners offering this?

i know that it is extensible and i could add my own stuff in, but the features i would want are pretty basic in requirement and are presumably things that a lot of people would be interested in. for example, call escalation based on sla and knowledge base (sharepoint addin maybe) etc

cheers
dan

[585 byte] By [Dan0001] at [2007-12-16]