The official website makes it pretty clear that line-in will be 100% supported, and I think it'd be nice opportunity to start fleshing out this sub-forum with useful and interesting topics..

How will it actually be handled on the software side?
WAV, MP3, AC3?
Sample Rate, bit-depth?
The N900 had pretty amazing audio quality (maybe the best), is this going to transfer to it's recording capabilities?

This is a genuinely awesome and surprisingly applicable thing for me, it is so difficult to find something that could do this for me so getting these tech specs is a big deal for me..

Thank you from me, and every other garage audiophile for including such an obscure feature!