Is there any way to change the priority of wired network to wireless connection in Vista SP2 Machines? The clients are connected both with wired and wireless and I need a GPO or some kind of solution that to change all first preferred network to wired. Disabling wireless when wired connected is not a solution. this can be handled by 3rd Party tools like Intel PRO Set Wireless Administrator Tools.

I know how to give preference to an individual machine, and this has to be done on all connections, e.g. Ethernet, Bluetooth and wireless, as follows: Go to Control Panel > Classic View > Network and Sharing Center > Manage Network Connections (in the left pane) then right-click a network interface, click Properties > scroll down and highlight, in turn, each of the TCP/IP settings > Properties > General Tab > Advanced (at the bottom) and click the Automatic Metric box to clear the tick, then enter the value that you want in the Interface Metric field. The system defaults to the lower or lowest number, so, if you set Metric to 5 in the Wired Network connection and to 10 in the Wireless Connection, the system would default to the wired connection. Obviously, when the cable is unplugged it would automatically switch to wireless connection. When the cable is plugged back in, it would take over the connection since it has a lower metric setting.

When I performed this change how can I monitor on that client that I'm accessing any web site over wired or wireless ? Is there any way to confirm that solution works ? Thanks

You will, obviously, have to test it before deploying it. Network and Sharing Center will show the current connection. Network and Sharing Center > Manage network connections (in the left pane) > View > Tiles will show all available connections.

How can I deploy these metric values to every client? Is it possible by GPO? Also is there any way to enforce an application to use wired connection when both are connected?

I dont know if there is one, although I vaguely recollect having seen a registry setting at some time in the past. I suggest you search the TechNet library or a Knowledgebase article.