>Without going too far over my head and paygrade - is it possible to create a help bubble that appears when you move your cursor over the message in messagebox().

You might consider switching to the Vista/Win 7 pane-style messages. They're designed specifically to let you have a way to provide more information with a click. Even if you have to support XP, you could design your own form that offers that capability.

Take a look at the Sedna Vista Dialogs for COM project.

Tamar