Entertainment Center: TVs, Stereos, VCRs and DVDs - installed inwall speakers now what?

Hi I have just installed some in wall speakers in my kitchen ceiling and I wanted to be able to listen to my stereo/home theatre system located in my great room but I would also like the option of listening to my Computer's Itunes at times too which is located in my office. I have run wire to the basement already from the speakers. What are my options? I would like to be able to switch back and forth from my kitchen area. I am also going to put a T.V in my kitchen eventually when I get the extra cash. Any advice would be appreciated. I realize I could just find a A/B switch and install one in the kitchen but is there a intelligent system, which is affordable, I can install in the basement which I could eventually connect other rooms too which will tap into the home theatre and computer?
Please any advice would be great,

Dharma