You can't tell if something is wired or Wifi without talking to the router directly: and they all work differently, so there is no one way to do that.
You can get MAC addresses on the LAN which will include Wifi connected devices:
Retrieving IP and MAC addresses for a LAN[
^] - it's in C#, but there are online converters which should change it to VB if you really need them.
[edit]Typos. Lots of typos...[/edit]