2002 Mitsubishi Eclipse oil light flickers on

When confronted with problems like this, I usually try to start with the easy stuff first. You just changed the oil a month ago so was there anything different happening there? Did you use a different oil or filter? I have seen oil pressure sending units fail and send false information, the sender might be bad and if it is try replacement and/or remove the sender and check the oil pressure with an oil pressure gauge, it should not go below about 7-10 psi with the engine at operating temperature and at an idle.