It is pretty straight forward. Here is a good DIY for just the radio:
http://www.8thcivic.com/forums/showthread.php?t=3534

otherwise here is some other DIY for other car audio related:
http://66.98.189.130/forums/showthread.php?t=3118

I have installed a Pioneer AVIC D2 recently, it was straight forward, getting the steering controls to work took some time. But, it works now.

The new Pioneer AVIC D3 is suppose to come out in March. I like how it has a knob for the volume instead of buttons.
http://gizmodo.com/gadgets/portable-...ers-226735.php