Never before have I encountered a website so straightforwardly named. Where has The Arabic Music been all my life? Every Arab nation is represented and so is almost every Arab artist who ever had their music recorded. Mumtaaz!
Also, if you're unfortunate enough to be like me and are cursed with tin ears, then you might find Maqam World's guide to the most common Arab instruments a bit of a godsend. It provides useful links to further reading and a little speaker icon you can click to hear what the instrument sounds like. Brill.