Donovan Nagel posts at Mezzoguild:
I often say that the hardest part about learning a language like Arabic is not the speaking. Speaking can be picked up pretty quickly believe it or not (made even easier by amazing sites like italki that connect you with Arabic speakers). The hardest part about Arabic is actually learning to listen – training your ears to grasp what you’re hearing.
What sucks is that this is the one part of language learning where there are no shortcuts. To become better at listening you just need time and lots of exposure to Arabic. You need to listen constantly. […]
Here you’ll find some excellent links to high quality material online that will improve your listening skills in Arabic. There are many many more than this online and probably a lot that I don’t know about but what I’ve listed here are high quality listening resources (mostly free, some paid) in a wide variety of dialects.
A tip o’ the Languagehat hat to Slavomír Čéplö (aka bulbul).