Nothing else needed, this receiver has AirPlay built in, I don't even know what an AirPlay Express is. Just plug the receiver into your router (a wifi adapter costs extra, luckily my router is on my stereo shelf so hardwiring isn't a problem for me, then once your iPhone connects to your wifi network, you are set).
I have one app for my phone that controls the receiver "iControlAV2", and the app called "Remote" that allows me to stream my iTunes library from my laptop upstairs (via wifi) down to my wired receiver.
The trick is to go into advanced options in iTunes and turn on homenetworking or some such, enter your Apple ID, and that's it. Once you run that "Remote" app on your phone, it will list your entire iTunes library from your computer as if it's on your phone, and push it to the receiver.
Pretty sweet if ya ask me.
edit: You know it's set up right when you see on your phone a little icon appear to the right of the volume controls in iTunes, Remote App, Shoutcast, whatever, hit that button and it will let you select what you want to stream to, in this case for me, it shows up as "Pioneer 1021K"
This is the icon you should see when it's set up properly, on the phone and iTunes on your computer:
And if you don't have an AirPlay ready receiver, it will still give you the option to choose your laptop as the music player, while using the phone as a remote.
But damn, this Pioneer receiver is some kick ass shit. Denon has AirPlay built in too I hear, but Denons have always been too complicated for me to use. Not to mention the Denon iPhone remote app looks pretty crappy.
Another great thing about this Pioneer, is it came with a little microphone on like a 30 foot cord for you to plug into the front during setup, then place the mic on the couch or wherever you'll be sitting. It will play tones, etc, and set itself up for you based on what that mic is catching on your sofa, chair, whatever.
Only issue is running the speaker wire to the receiver is a royal PITA if you don't have banana plugs. Be prepared to do a lot of cutting and stripping to get those cables into the back, or just buy the damn banana plugs. I got the plugs, but realized when I got home I bought the kind that require soldering heh, so I just said screw it and wired it the old fashioned way, not fun.
Sound quality is phenomenal to me, but I'm not qualified to comment on that really, I just replaced a 100W TEAC receiver that only did composite connections (didn't even have an S-video plug on that old thing heh)Edited by javyn - 2/22/12 at 11:08am