Two questions regarding my 2000 Explorer SOHC.

First Question (Poor Idling P0101 trouble code)
Well basically I have the same issue as everyone else with poor idling when the vehicle has cooled down. IAC was just replaced less than a month ago. Went to Auto Zone and got the trouble code read to me. It read P 0101, Mass Air Flow (MAF) Circuit Range/Performance Problem. The guy at Auto Zone told me it was a leak somewhere and I had to locate it. Could this be directly related to the MAF sensor or just a vacuum leak somewhere? I can definitely hear a whistling sound when I start it up, and decreases in strength as the engine warms up. I have looked and have yet to have found a leak. Any suggestions as where I should start? Where is the MAF located exactly, so I can take it off and clean it up?

Second Question (Alarm)
My anti theft system was working fine until two days ago, when I unplugged the battery and changed out a broken fuse. The fuse was just my cigarette lighter. I'm not sure what I did during this process, because now my alarm doesn't work, and I can only start my truck when I press the button located underneath the steering wheel. My keyless entry works fine as it did before, and instead of my alarm chirping when I lock the doors, it just honks twice to verify it is locked. I kind of, like the fact that my truck can't get started without pressing the button, but now my alarm isn't activated. Any instructions on how to set the alarm back to the way it was normally?

Any help will be greatly appreciated.