Once you have mastered the functionality of each toolbar button in Outlook 2007, the ScreenTips can become somewhat annoying and distracting. You can easily disable ScreenTips so that they no longer appear when you mouseover the buttons on your toolbar.
1. Open Outlook.
2. Click Tools and select Customize.
3. From the Customize window, select the Options tab.
4. Go to the Options section and uncheck the Show ScreenTips on toolbars checkbox.
5. Click OK.