Completely Stuck, HELPME!! Options

[mancabbage]

right here goes, me and my band want to record a demo that we can turn into mp3's.... Im using an new ibook and have no idea about where to start - i looked at some software and as soon as im ready im pretty sure i'll download the desk light trial for editing, etc. We want to record our tracks seperatly as well so we can edit them in the computer - thing is how the fuck do i get these sounds into my computer 0n a tight (very tight) budget? i have usb and firewire on my ibook so im assuming ill need some kinda connector box that will conect to a normal mic lead and will send the info thru one of these ports??? i only really need one mic lead type input because we have a PA system at the studio we jam at so we can mic the drums up with loadsa mics then set the levels on the pa and take a wire out of the pa into whatever i am using to connect to my computer??! but what do i use? ive searched the net but all i can come up with are biiig home studio expensive things when this is not what i need at all - just something that will let me plug a mic into it that will allow me to record the audio in my mac ??? so can someone help me and tell me what i need any advice - steps - suitable products- anything would be of help - cheers