Not sure about USDM models, is it the same interior as a Gen IV Legacy? If
it is then grab the shift lever surround and pull it up, it should pop out
with a little force. On an MT car, unscrew the gear knob; on an auto, you
need to pull off the indicator ring around the shifter first.
Undo the 2 Philips headed screws at the rear on each side, then lift up the
back end of the console surround strip and pull it back towards you, it's
held by  a couple of clips by the radio / AC units; repeat for the other
strip. You can now see 3 Philips screws on each side of the radio unit (one
is buried quite deeply); undo these and it will come free.
I don't know if the USDM cars use the same stereos as the EU cars (Kenwood),
if they do then you have no chance of adding an Aux input as there's nowhere
to fit it and there's no Aux mode on the stereo.
Martin

I want to add an audio input jack to the radio on a 2005 2.5i OBW but
first I need to get it out of the car.

Anyone know how to remove the unit? I can't see any obvious retaining
screws etc.