I have iMac 2011 running 10.6.7 I have updated itunes to 10.5 and my iPod to iOS5 but i don't have the Wifi Sync Box. What can i do this is very annoying
Is your iPod connected to the iMac with a USB cable? The option only shows when the device is tethered. You then enable it, Apply and disconnect.
Also make sure your iPod and iMac are on the same wireless network. It won't work if they aren't.
You need to be on Snow Leopard 10.6.8 for the Wi-Fi Syncing option to show up for you. Upgrading from 10.6.7 to 10.6.8 should solve your problem.
http://support.apple.com/kb/TS4062