iPhone & iPad almost instantly forgetting networks
There are issues with iOS6 and some Netgear products.

This is taken from http://kb.netgear.com/app/answers/detail/a_id/21865 which is directly linked to the products page on the Netgear site.


  There have been widespread reports of wireless connection and speed
  problems with devices using Apple's newly-released iOS 6 connecting to
  NETGEAR products. The problems that you are experiencing may be due to
  a recent upgrade of the Apple iOS 6.  While the nature and extent of
  the iOS 6 and Wi-Fi connectivity issues are unknown, NETGEAR will do
  our best to continue to monitor the updates from Apple and continue to
  work with our customers to ensure that we can help provide support and
  work-arounds (when possible) to get your devices connect properly.


There are several other pages and forums linked from there, I don't have enough time (or a way to test) which of these actually fixes the issue.

If you find one of these resolves your problem, please post the solution back here for others.