WiGo by cam-do.com claims to let you do this.
I tried it out. Windows noted that I was connected at 65mbps, however the file file transfer was horribly slow.
I was trying to transfer 3 files at a total of 5GB, and over about 5 minutes, only one file transferred 65mb. It would have taken hours at that rate to transfer the files (and instead of charging the battery, like using a cable would -- this was draining the battery).
FYI the UI is neat and simple, it's a great app for changing the settings etc, and it fires up a VLC streaming preview.
Browsing the filesystem is done via a web server, you browse it like a webpage and "download" the files.
I also noted that going to help->about states that it expires in 25 days...