Lookout for Outlook was one of the best pieces of productivity software ever created for the Windows platform. It makes Outlook, one of the shoddiest and crummiest piles of code ever sold, actually work.
Microsoft bought it and it disappeared. Allegedly MSN search has some of it.
I use version 1.2.8 dozens of times a day. By chance I see there was a quiet update to 1.3.0 last February -- almost a year ago. Worth trying.
Update 1/11/06: Hmm. I think 1.3.0 is not rebuilding my indices every hour as its supposed to. Alas, I fear I did this update once before -- with similar consequences. I withdraw my recommendation. I guess 1.2.8 is as good as it's going to get.