This one might scare you pretty good the first time you see it. When you launch IIS Manager either on a MOSS WFE or remotely connecting to a WFE nothing populates under your server name in the left pane: not even showing folders for App Pools, Web Sites or Web Service Extensions.

This is fairly common (haven't had a chance to see if it was fixed in SP2). It looks to be a memory leak of some sort as it seems to happen over time.

Luckily the fix is very simple: simply restart "Windows SharePoint Services Search" and "Windows SharePoint Services Timer". No iisreset is needed afterwards from all the cases I've seen.

NOTE: Reader Richard suggests the hotfix KB946517 may resolve the issue. I will try shortly and confirm. Thanks Richard!