I am not Electrically inclined so I am sending this to all the Gurus...

I have the non-HK stereo with Nav and Ipod... I would like to have the Sirius radio as well.... any way to put a switch at the connector for the Aux (where the Ipod plugs into the radio) so I can connect both and switch b/w the two as desired?

 

Yep, possible and not too expensive. All you need is a miniplug audio switch.
A company called Plantronics is selling something they call a ".Audio PC Headset Speaker Switch" which seems to be going anywhere from $10-15 online. It should do what you want but might require some extra parts (some miniplug gender changers).

 

I may not have explained myself well. I am looking to switch the input in the back of the Headunit... what is the input, is it a miniplug?

 

What I was suggesting was that you have the one AUX input but you run the switcher to that one input. So you have the switch plugged into the aux and then the iPod and Sirius into the switch.

You could always get one of the Sirius setups that uses the CD Changer input instead and save yourself some trouble.

 

I would like to be able to control the Ipod w/the head and steeringwheel unit controls

 

Well in that case you are talking about something other than the AUX hookup. The Aux hookup is just a line in to the head unit, no controls or anything. In which case I can't be of much help as I don't have that type of setup.