When Microsoft officially unveiled Windows Phone 7, and unveiled that the device would sync with Zune Software, there were a lot of Mac owners out there trying to figure out how, exactly, they'd be able to utilize a Windows Phone 7 device, considering that Zune Software doesn't work for Apple-branded computers. That's where Windows Phone 7 Connector for Mac comes in. A tool to sync your device, and bring your media from iTunes (that's not still protected) onto your Windows Phone 7 device.
But what about the Zune HD, which has been out significantly longer than Windows Phone 7? It looks like thanks to some minor tweaks, found by some members at ZuneBoards, you can actually get the WP7 Connector for Mac to register your Zune HD. It isn't as simple as plugging in your HD, unfortunately, but the steps aren't too extensive. Of course, if you're not comfortable changing some settings around, then you may not want to head on through the source link and find out how to do this.