I am assuming you are talking about a 12V car stereo (that mount in the dash), and you want to bring it inside the house to either a 110V or 220V system.
If this is the case, then I would suggest getting a nice power supply (12 - 13.8V DC output) I would say getting one that is designed to power HAM radio equipment would be the best, as they tend to be very well built. As far as the speakers go, it would be just a matter of following the instructions of the radio (assuming its after market) to connect them properly.
If you need to get things like amplifiers and sub-woofers working, this would require a few more things like possibly a car battery to run them from, and a good sized capacitor that is designed for car audio. Not to mention a way to charge the battery after you were done using the extra bits.
Matty-