How to set up a ceiling speaker system?

Just bought a house and trying to set up some speakers for ambiance/background music. I have the speakers and wire all set up to the same place, but I'm not sure how I should hook it all up. Most importantly I just want to set up an indiscreet or in-wall receiver to control it. I'm mostly just looking for something to control the volume and probably set up an iPhone dock that hooks up through the microphone jack. If possible, maybe an RCA jack for random occasions. So mostly I'm just looking for something to hook the speaker wire into and control the volume/playback.

Is this something I should get an amplifier for? Is there anything else I should be more worried about? Is there a cheap in-wall control anyone can suggest?

Built in home audio is a bit different than simply having a room wired with, say 5 in-wall speakers for 5.1 audio. Ditto for just adding an extension pair of speakers in another room.

Typically you'll have the speakers installed with a volume control on the wall, and that volume control is either an L-Pad or a higher-power speaker controller. These are not cheap, but the impedance must be kept constant - you don't have a choice here.

You have 2 options with the speaker wires. You can have a series/parallel connection within a junction box in the attic or similar hidden area, or have all speaker wires come out at a central point and connect to a speaker selector junction box. You will need one with impedance protection - no choice here either. A receiver would connect to the speaker junction box - using only one set of speaker outputs from the receiver or amplifier.

And now you know why those A/V installers charge so much, and why it's cheaper to do this during new construction! There's no cheap way here.