I assume you have a PC or Mac already if you have iTunes.
Get a DAC - but research to see which one suits your needs - I use a DACMagic from Cambridge Audio @£200, but there are others like Beresford (cheaper at just over £100 I think) or more expensive ones going up to thousands of pounds.
Connect DAC to Amp via normal phono plugs, connect DAC to computer via co-Axial plug or USB or optical lead depending on which computer you have and which DAC you choose. Start iTunes, stream music to DAC -> Amp. That is it!
If your PC/Mac is too far to connect to DAC via leads, get Apple Airport Express (£65) which will connect with iTunes wirelessly (assuming you have WIFI network at home), -> connect Airport Express to DAC via optical lead (no USB).
Get a second Express and you can steam to that too in another room.
I have a CD player costing £1000 about 10 years ago and I cannot really tell the difference between that and the iTunes/DAC combination, BUT that is because I play Apple Lossless music files from iTunes. If you buy CDs, you can rip them into iTunes losslessly or download music from iTunes but keep the bitrate higher at 256.
If you have iPod Touch or iPhone, you can use that a remote control to control the music. Pretty cool.
Lots of info here and you may not understand all of it if you are new to the DAC game but be patient... I managed to set everything up from scratch and very happy bunny! And I am certainly not going to buy another CD player again.