Is it possible to temporarily disable the screen timeout?

Often, during updates/downloads or backup operations I would like to **temporarily disable the screen time** ( found under the '*menu - settings - Display - Screen timeout*' ) without having to navigate to the above menu setting . Anybody knows of a good **widget** which does just that : either disable the screen time ( by just clicking the widget ) , or by setting it to a high value / back to short value ( also by just clicking the widget ). Or is there any other easy way I have missed ? I am running Froyo on Samsung Galaxy S.