Warranty Plugin for SCCM Client Center (click the link for my blog post and more info).
Unzip and put the files in "C:\Program Files\Common Files\SMSCliCtr\Tools" and the tool will be available from the "Tools" menu inside of SCCM Client Control.
Currently supported systems:
Dell via (http://xserv.dell.com/services/assetservice.asmx)
Please let me know if any other hardware supplier out there offer a similar webservice for getting warranty data and I can add those as well.