Shooting live music is tricky but can be rewarding when you review your pictures. The biggest problem is the lighting. It varies all the time both in colour and intensity, from almost black to the brightest white. I've found that I have to shoot on a manual meter setting and be prepared to rock the dials (no pun intended) being careful not to drop your shutter speed too low, this will depend on how fast the artists are moving but try not to go below 160th or better still 200th. Don't be afraid to open up your aperture but make sure your focusing is accurate. I've used Nikon D3s and 4s and I'm currently using Canon 5D Mk3's. With both the Nikon and Canon I use the ubiquitous 24-70mm 2.8 and the 70-200mm 2.8. These two lenses are good for most things but perfect for shooting music. Your ISO will depend on what you can get away with, you almost need to set you shutter speed then a wide aperture and then you can see what sort of ISO you'll need. Live music photography has a strong documentary feel to it so it really isn't an issue if you're getting a decent amount of grain in the images, it can add to the soul of the pictures and after all, it is noisy! This is a kind of joke but in reality noise (grain) and noise (sound) can complement each other. Shooting with the Nikon D4 even at 3200 and 6400 ISO gave me such clean pictures I would often find myself adding noise to add a bit of energy to the picture.
One of the key disciplines when shooting live music is anticipation. If you can anticipate where the lead musician is moving to, you can be prepared for the shot. With vocalists you find their faces are hidden behind the microphone, being to the left or right of the mic will give you a cleaner shot. Don't always shoot with your finger anchored on the motor drive button, firing machine gun style isn't always the best way. I always shoot single frame and I can then pick the very best expressions.
It;s great fun shooting live music, have fun and try and reflect the feel and and music the band are projecting.