I'd probably use the CDR/Tape output, which is at the bottom of the ins/outs panel.
With the computer, you will need some type of software that records the mic input and saves the file to WAV. From there you can use something like Audacity ( free Windows software ) to edit and convert to CDA or burn to a CD. You can even use Audacity to record the audio then tweak it, get rid of pops, and then convert to whatever format you need. I would just convert to FLAC and burn those files to an archive CD, or better yet, a DVD-R or BD-R.
HD-DVD = 94
Blu-Ray = 120 ( 24 Warner red2blu )