I've seen the Wi-Fi sign pop up whilst underground but wasn't fast enough to register with Virgin to see if it worked, as I quickly went "out of range".
Like many other Oystercard holders I received an email from TfL yesterday which said
"I am writing to let you know that WiFi services are now available at the following Tube stations:
Euston Green Park King’s Cross St. Pancras Oxford Circus Victoria Warren Street
If you have a WiFi enabled device, you will be able to check for the latest travel information online and for example access your emails. The signal will be available in ticket halls, corridors and on platforms. A one-off registration is required to access the online service which will be free during the summer. Access to travel advice will remain free after the Games. We plan to have 80 Tube stations WiFi enabled before the Games. For more information, please visit tfl.gov.uk/wifi ."
I haven't been at any of the above stations long enough to see how the Wi-Fi worked, have you? I'd been keen to hear what experiences you've had accessing the free WiFi at stations and whether it's worked at deep level platforms. Thanks.