If you want to exclude some items from iPhone Search to speed up search or any other reason then you may follow the method written below to do that easily. The method to exclude some items from Spotlight search is same for iPhone 3G, iPhone 3GS and iPhone 4.
Tap “Settings” on home screen of your iPhone.
Tap “General” option.
Tap “Spotlight Search” option.
Here, just Tap on the items to uncheck and exclude from Spotlight Search.