Disconnecting the battery will reset your computer which wont hurt, but probably wont help you in this case.
If the engine runs smooth at other RPMs it would seem to point to problems with the IAC or possibly some type of intake leak. Check all the hoses around the intake area. The spark for each cylinder can be checked by pulling 1 wire at a time and noting the effect. Each wire should have about the same effect in making the car run more rough. If you find one that doesn't make a difference, then you found the bad plug or wire (or worse). Try to confirm that the ignition checks out good and then start testing the intake/fuel system. Run a bottle of injector cleaner in your next couple of tanks of gas.
