First ff, I hope you have a fast lens, f2.8 or quicker, as you'll struggle to get any decently lit shots if you don't.

Also, your light meter will be going crazy so pay no attention to it what so ever, it won't give you any accurate readings.

A good starting point is ISO 1600, wide open aperture, and start from 1/60th of a second for shutter speed, if it over exposes then up the shutter speed. You can up the aperture but if you want to freeze any shots shutter speed is the way to go.

Use flash if you must but make sure you ask all the bands, and if you do, use a shutter speed of around 1/20th so your letting as much ambient light in as possible, and also if you have the option, set the flash as more of a fill-in flash, so it's 1 or 2 stops less powerful. Doing all of this lets you keep the atmosphere of the gig, and also doesn't blind the band. Here's a photo of what I mean:



Let us know hoq you get on. If you have any more questions then let me know, I do quite a lot of gig photography, especially in clubs, so I know what I'm on about (not to sound big headed).

Chris

Good lens for gigs are 50mm f1.8 or if you can strech 50mm f1.4 around £180.
but its fast,is brillant for low light and is general a brillant lens to have.
You can pick the f1.8 up for about £70ish