I've also tried using a pringles lid cover over the built-in flash for short distance fill-flash... works great to diffuse the flash. ala Stofen 
Shannon...about using the flash.
Here is what I do sometimes when I find using the flash creates light that is too harsh :
I use the shiny side of a CD to bounce the light to the ceiling . Just make sure you lock the focus first (half press) in case the CD would get in the way.
It worked great on a few occations. Here is a pic of my sofisticated ( :/ ) setup with my G5

Good luck .

