yes
It is near impossible to tell objectively which audio adapter is the best one. It also depends on the device for which the audio adapter is needed. If one needs a stereo headphone jack adapter, Dynex would be a good choice.
You could find an audio adapter at any electronics store like futureshop or BestBuy. My best guess for great value of a audio adapter would be either futureshop or BestBuy in my personal opinion.
The StarTech.com USB Stereo Audio Adapter has received some very good reviews.
If someone is looking to buy an audio adapter, he can visit the shopping center and head to the local stores that have electronic device running businesses such as 'Dick Smith'.
One can buy an audio adapter online from web sites like eBay, Amazon, and DealExtream. One can also go to local electronic stores like BestBuy and Staples.
No. Line in is for audio, but midi is for midi.
An USB audio adapter can be purchased in every electronic store. Alternatively one could buy them at websites like Amazon, LogiLink, or, if one doesn't mind an used item, at eBay.
The Lynx CBL-XFDR18 S/PDIF Adapter may be the best.
No
No, you will need an audio adapter.
What you are looking for is an audio interface but there also adapter like interfaces for example the Stealthplug by IK Multimedia.
You will need a 3.5mm Audio Earphone Headphone Microphone Adapter for Apple iPhone 3G to plug in your headphones.