The javascript rollover status bar message is an old trick, but this easy addition to the <BODY tag of your page will set a default satus bar message. Try it here. Rollover the menu bar on the left to get PixelPusher.com's standard status bar messages. When you're between rollovers, or off them altogether, you'll get the status bar message, "Default message".
Here's the code to put in your <BODY tag: onload="window.defaultStatus='Default message'"