Like others, this didn't work for me out of the box, and I wasted many hours installing, uninstalling and talking to tech support in a vain attempt to get Win 7 (64 bit) to recognise the card. It turns out that the driver which comes on the CD is very outdated (2007!), and new installation exe was released on 26th July 2010.
Go to http://kb.netgear.com/app/products/model/a_id/2605, and click the 'Download' tab. This will show a file labeled "WN311B Software Version 7.1". You have to click on the yellow button saying 'Right-click and save to download' (don't do 'save target as'!), and then click on 'Continue without registering' on the next registration page. You shoud then be able to download the exe, called "WN311B_setup_V7.1_230-10342-09".
Now - uninstall the previous stuff from the CD, and remove the adapter card from the PC. Run "WN311B_setup_V7.1_230-10342-09", and it will install the working driver set. IMPORTANT : When it gets to the part where it asks you to shutdown the PC to seat the card, CLICK 'NEXT' at the bottom! This continues the software install. Only once this completes switch off the PC & put the card in (with the antenna).
When you restart, it will install the drivers, and the much dreamed-off config part of the install will start up! You can then add in your wireless network details as standard, and Bob's your uncle!
The adapter itself is great!! Much faster than my previous dongle. So 9/10 for the product, but 1/10 for Netgear a) selling this is Win 7 compatible when it wasn't, and b) not providing a Win 7 driver *many* months earlier!