2008 Audi a6 anyway to play music from smartphone

Your 2008 A6 should be able to pair a phone using bluetooth. The owner's manual is built into the infotainment console for reference on how to do this.

If that doesn't allow music streaming, there are I beleive TWO external AV input jacks to connect.

The built in Bluetooth won't allow the playback of music/media - it doesn't have the appropriate BT profiles and will only connect for phone purposes. Audi didn't add that in until 2012-13, and yes it's extremely annoying!

If you've got the MMI 3G with the Audi Music Interface connector in the glovebox you should be able to get a Bluetooth adapter that connects to that port and in turn to the phone via BT (this is what I have in my RS5). This doesn't work for pre-09 cars that have the MMI 2G though IIRC so you'll want to check which variant you have before ordering any kit.

Not sure if it holds true for all adapters but at least for mine it's a "dumb" connection - mirroring the functionality of a plain AUX IN lead so you can't control playback or get track info etc this way so you still have to use the phone to select and play tracks.

I think on the earlier Audi's they had aux inputs but it was a special lead that went into the back of the head unit.

If your lucky the lead maybe in the center console between the seats