Hi,
It really depends. Are you mining just on your CPU or are there GPUs it is using too? If it is only mining on the CPU you will probably have trouble getting any accepted because it is just too slow. If it is using GPU(s) too, then it might be a different problem. If you tell everyone a bit more about the config you might get some help. ;-)
I just started using GUIMiner and i put in my info ect, and start it. It says 0 accepted and 0 shares and it has been running for a long time. Is this normal or is something not going right?