Hi Nikhil,
Under Windows 7, the 802.11 interface is simply named "Microsoft" for some unfathomable reason.
Unfortunately, because WinPCap (and by extension Wireshark) does not utilise the new APIs/mechanisms for capturing raw 802.11 frames that are provided by NDIS 6, you'll only see synthetic Ethernet frames if you capture in "Local Mode"/Station Mode.
However, it is possible to use Microsoft's Network Monitor 3.4 to capture 802.11 frames (with a poorly-designed, proprietary pseudo-header, of course) to a file that can be read by recent versions of Wireshark; in either Local Mode or Monitor Mode - providing that you're willing to accept various caveats:
- 802.1X frames from Ad-Hoc networks are seemingly ignored/dropped - although other data and management frames are captured
- Wireshark cannot currently handle "type 7"/Raw IPv6 frames in NetMon capture files - so some frames may appear to be missing, or your file might not load as you'd expect
- The capture engine and pseudo-header have a habit of causing management frames to be corrupted or treated as Malformed packets within Wireshark (and I've encountered Beacon frames that have invalid TLV data blobs attached to them post-capture, which were never generated or transmitted)
I hope that helps,