Phone Search is a Windows Phone 8 and 7.x app that lets you search your calendar and contacts from a central location.
You can search by keyword, address, phone book, date and all the details of your calendar and contacts will be scoured. If your search yields no results, you will be given the option to search the web via Bing. Your last ten searches can be saved and search terms can be memorized so that it can be shown when the app restarts.
Due to limitations with Windows Phone, Phone Search can't search emails, text messages, music files, to do lists, or apps.
Phone Search is a fairly simple app for your Windows Phone but if you're searching for an appointment or need to match a phone number with a contact, it's not too shabby of an app.
Phone Search is a free, ad-supported app that you can find here in the Windows Phone Store.
Thanks, Mark, for the tip!