I recently purchased a Shure SM-57 microphone that I'm just thrilled with. The thing I would like to do it use it record an acoustic piano and a acoustic guitar via a PowerBook. Since the microphone has an XLR cable, and the PowerBook has a "Line In", I'd like to know the best way to connect the two. It is my understanding that you need some sort "preamp" to amplify the signal coming from the microphone so it will work with the "Line In" port. I've been searching the internet and all kinds of forums all evening trying to understand how this works, but I'm still a little confused. So it would be helpful if someone with some knowledge could just "lay it on the line" for me. All I need is a simple, conclusive explanation. So the sum of my question is how to record from this Shure SM-57 micronphone to a PowerBook's "line in" port. I don't need anything fancy, but I do want professional quality. Any help would be wonderful. Thanks.