Docking station for an iphone

What is the source of what you are trying to play from the iphone? Are you looking for convenience or highest sound quality? What inputs types are on your dac? 
For convenience you can get a usb bluetooth receiver that will attach to the dac and grab any signal from the iphone or other bluetooth device. 

As with most things digital, a question usually leads to a few more before a good solution arises :-)  Cheers,
Spencer

sbank what options do you know of?   I like sound quality and convenience.   Might sacrifice some latter for teh former if needed.

I'm pretty sure that Wadia made one.  I think it was the 171i that worked with the iphones.

Pure i20 is compatible to  iPhone 4.......

Yes but there is an adapter for the lightning connection of the later versions of the iphone. I use this and it works fine. I have my I20 running out to a Bifrost Uber extrenal DAC. Sound fantastic!