after a software update...itunes 9 I think. The itunes icon no longer shows up in the dock. There is an empty space where it use to be and I can click on empty space and it opens up itunes but the icon is not there. After updating to itunes 10 it is still missing. This did not occur on my iMac just my 15" MacBook Pro.
iMac20 2GB RAM, Mac OS X (10.4.9), G-TECH 250 GB HD, DAC-200 Converter, Sony HC7 Camcorder
Hold the empty space with your pointer as if there was an icon there and move it to the trash ..Now open your applications and drag the itunes icon over to the dock .. There you've just refreshed your dock icon