There's another good post over at Verso on the subject of Serio and the Service Catalog. This links into George's posts below about Availability statistics (where the subject of representing Key Services in the CMDB is discussed).
Serio Ltd.83 Princes St.Edinburgh, EH2 2ER
(+44) 131 331 1535
689 SH2Tauranga,New Zealand
(+64) 27 5772423