I take it you mean importing old analog masters from tape, tarting them up a bit and slapping them on CD?
If this is the case, then have a look at T-racks. It's a neat 24-bit capable app with EQ, limiting and compression and an output section.
It'll also run as a plug-in in Garageband (well, the AU version will).
It depends how serious you are about audio quality, I'd go 24-bit/96Khz into Protools and master with the Waves Diamond set, but I'm picky. You could record 16-bit/44.1Khz directly into Garageband and master with the plug-ins in GB if you weren't too bothered.