Brakes: Troubleshoot Dash Light
Their are several possible causes for this:
Your brake fluid is low. Fill it, and you should be good to go.
If this does not fix it, another reported solution could be to check the connector switch on the e-brake. You can readjust this by taking off the center console, and you then should be able to see the plate that the e-brake touches to make the light come on.
A few members have also mentioned that under very hard acceleration, your e-brake might lift slightly (especially if it is loose), which also might trigger the light. Their is an adjust the tension thru and access hole in the bottom of the center console. This will allow you to tighten the brake cable.