A workaround solves the problem of sync for mobile devices in iOS5, as described in this article from MacObserver. Jim Hamm declares that Apple needs to address this complicated process in an update.
This morning we have a reply from John Carter to shed more light on the situation: "I don’t want to rely on using WiFi for backing up iTunes to the iPhone and vice-versa, so I always connect the iPhone directly to the Mac for that purpose. However, anytime I make a change to my address book or calendar or add a photo to Photo Stream on either the Mac or the iPhone, just being at home with the Mac turned on takes no more than 15 minutes to see the change on the other device. Now that’s real handy! I don’t have to connect the iPhone to the Mac and bring up iTunes just to update my iCal or Address Book or photos that I took on the iPhone to make them available to iPhoto."
To follow-up: this article just came (11-1) from SmallDog to clarify the method of wireless sync with iTunes. See if this helps.