iRig Mic not working with MacBook

Just bought the iRig Mic - it works perfectly well with my iPhone 4.

But when connected to Garageband '11 on my MacBook (10.6.8), I can't get any sound out of it. I plugged the mic into the 3.5mm mic-in port, and also tried the headphones port as well - no sound from either attempt.

I did go into Settings, and I selected the input sound source. No sound.

Any advice on this pls?

Another thing, I tried using iRig Mic with a DSLR camera, but ended up with no sound on the video also.

If anyone knows anything about this, too, pls advise!

Thanks!

Have you tried looking in the Audio MIDI Setup?

Applications > Utilities > Audio MIDI Setup

In there click the + sign in the bottom left hand corner and see if it picks up your iRig Mic