For a long time, I was looking out for a simple search option for MS Outlook 2003. I could not convince myself to use some desktop search tool. I felt that most of the desktop search tools are CPU hungry and could slowdown your system at critical junctures. Finally had time and energy to find the search plug-in.
“Lookout is a lightning-fast search for your email, files, and desktop works with Microsoft Outlook. Built on top of a powerful search engine, Lookout is the only personal search engine that can search all of your email from directly within Outlook - in seconds. You can use Lookout to search your: Email messages; Contacts, calendar, notes, tasks, etc.; Data from exchange, POP, IMAP, PST files, Public Folders; Files on your computer or other computers.”
Microsoft bought this company way back in 2004 and started un-supporting it. So today to get this plug-in you have rely on third-party web-archives.
There is no support for this plug-in. So use your own discretion.