2004 Other Toyota Models Brake light("!") Indicato

Hi,
I have a 2004 Toyota Solara V6 standard model, hardtop not the the convertible. The check brake light came on and I looked at the manual and it says to either check the brake fluid which I did and its fine, check the emergency brake which is off and if all else fails take it to the dealer. The Brakes have been fine, no problems yet. I just don't want to spend a fortune at the dealership. Any ideas why the light might have came on. It came on today right after I put air in my right front tire. Any ideas? I don't want to spend a fortune if its a minor problem or if I can just reset the swith. Any help or knowledge of this problem would be appreciated. Thanks for all of your help.