Maint Req'd Light on! Help!

I went 2 the mall... and then when I cranked up my car to leave my maint req'd light came on. I'm at 158,000 miles and we just replaced the radiator and thermostat last week and it was fine. Then we got my a/c fixed so everything was going fine until this. Could there be nothing wrong and I'm just supposed to go in to the dealership for a checkup? I read there is a reset button. If I press that it will go off... but if there is a problem it should come back up right? I think I might try that. I went 2 AutoZone for the free check engine light testing and they said it was only for Integras 96 and up. So I got a guy 2 come out anywayz... and he said he couldn't find the hookup. So my questions... should I press the reset button? And where is the hookup and will it work?