Here is my suggestion. Buy this one if you dont care about being use your headset setup to talk as there is no mic in this adapter but it is small and works. (would be great with an Ipone heaset if it works like the V-Moda Vibe Duo)
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I use this one. It has a mic so i can take a call while I am using my headphones. It works great. my only compliant is it adds a couple feet to my cord which isnt great but is a minor issue.
Ebay Link
They are both under $10 shipped.
Even though most people cannot tell the difference between 320 and 192 Mp3s you will definitely not be able to tell the difference if you are not using really good to great headphones.
I have two pairs that were $100 each. I bought them for my ipod but also use them on my Mogul. They are V-Moda Vibe which are awsome but have alot of bass and the others are Bose Tri-port IE which are really comfortable and sound really good. There are more expensive ones that probably sound better but my opinion was i was just throwing away money because they didnt sound any better to me.