When I looked at the 4310ci photos on the Denon web site, I didn't see a wifi (802.11 a/b/g/n) antenna jack on the back of the 4310-the only external connection of relevance is the Ethernet port. As far as I can tell, only the 4308 and the 5308 have built-in wifi, so you will need to get a wireless access point and hook it up to your Ethernet port. You can use one of several wireless access points with an Ethernet port-I use an Airport Express with a switch that is connected to my AVR-3808ci and my Oppo BD-83, but there are other options that would work as well. You can also use some wireless routers as access points, which could eliminate the need for a switch if they have one built-in and could provide more signal power (and less cable clutter). BTW, the Xbox "antenna" is also a wireless access point, not just an antenna-the 802.11 wireless transceiver is built into the add-on, not inside the Xbox.
FWIW, the Airport Express works great for Internet radio and the periodic firmware downloads, and it also provides an analog/optical port (ie, Airtunes) you can use to stream audio from iTunes to an input on your receiver.
