Your signal path will go like this:
mic--> preamp--> I/O (inerface)--> computer (recording software)--> hard drive.
Presuming you have the mic(s) and a laptop, all you need is the preamp, the I/O and the software. I see on Seetwater's site that Digidesign just came out with the 'Mbox 2 mini.' It is an integrated pre and I/O (I/O converts the analog signal (from the mic) into a digital one (that the computer can use). The cost is $296 AND--it comes with Pro Tools LE software! Yaee!
Your DAW (digital audio workstation) will consist of the Mini (if you choose that one), your computer and Pro Tools (the software). You can only do one track at a time but it sounds as if that will do for now--and--you'll be making digital recordings...a FAR cry better than those old cassette 4-tracks! (I know...I've done that too).
http://www.sweetwater.com/store/detail/MBox2Mini/