iPhone - WiFi Fix

Apple - Support - Discussions - iPhone 3G cant detect any WiFi since ...: "

1. Change your WLAN-/WIFI-station to non secured (no password)
2. Try to connect your iPhone - most probably it won't connect
3. Change airplane mode to 'On' and wait 10 sec
4. Change airplane mode to 'Off' and wait 10 sec
5. Change airplane mode to 'On' and wait 10 sec
6. Change WIFI to 'Off' and wait 10 sec
7. Change WIFI to 'On' and wait 10 sec
8. Try to connect - most probably it will connect!
9. Now change your WLAN-/WIFI-station to secured 128-Bit-WEP and give it a password
10. Change WIFI to 'Off' and wait 10 sec
7. Change WIFI to 'On' and wait 10 sec
8. Try to connect with your new password - most probably it will connect again!

In my case it now even connects easily to all the other networks again now!