how to show a message from a blender script?

Is there a way to show a simple message box with a text from a blender script? For example if i'm having an error during execution.开发者_运维百科

Update: The link does not exist officially any longer and I stopped developing for Blender. The old 2.5 cookbook is still available in the internet archive at:
https://web.archive.org/web/20120824033549/http://wiki.blender.org/index.php/Dev:2.5/Py/Scripts/Cookbook/Code_snippets/Interface#A_popup_dialog

Have a look at this code snippet for an error dialog / message window. After selecting, a (text) file a message pops up when the word return is read. It works basically but I had to hit escape to make the box disappearing (on Mac OSX) because there was no reaction on mouse input.

Seems to me that there is no generally recommended way for displaying message boxes in Blender 2.5. Maybe the designers want to encourage the add-on programmers to use the self.report for messages and the tool shelf for getting operator's input instead. But this is just an assumption, I am still a beginner.