I wrote this up for somebody, thought I'd share it here too:
It's pretty self explanitory, but here's a quick tutorial if you want the pod visible instead of simply putting it in the glovebox...uses the belt clip *thing* that comes with mini iPods.
It's connected with an aiNet cable that plugs into changer-ready Alpine HU's. Sounds great, but it's an AUX input and not controllable from the HU.
Here's what you need, and where to drill the holes:
Here's how you do it:
The only tricky part is removing the pin from the belt clip. Once that's out, you can easily drill and bolt the clip piece to the HVAC vent assembly. The pin pushes back in really easily. I used a piece of double stick foam tape to keep it from spinning, and a hard rubber washer on each side of the bolt.
All done. I just ran the RCA/mini cable through the heat vent:
And a bling-blangin' night shot:
FYI: The HVAC vent assembly is ~$70 from subaruparts.com. So if you're worried about drilling through it... don't.