For your camera, that would be a *really* high ISO. I was considering the G10 when I replaced my old camera for this tour. Noise on point and shoots at higher ISOs can be a real issue. And here's the thing- though there are low light/difficult light portions of a U2 gig, for the most part, the...
Sicy, YMMV but I only shoot manual if I'm at a gig. For ideas on exposure/shutter speeds and all that stuff, I suggest browsing on flickr for shots you like and checking out their 'more information' links.
For example:
Flickr: More detail about
That'll let you see the exact settings used and...
I think the most important thing in any camera is adjustable manual settings-- you need to be able to control your shutter speed and aperture settings, as well as how you're metering, etc. Especially at a U2 show where the lights can change pretty dramatically. Even if it's not a top of the line...