Same problem... Things got really weird again this week-end as both my iPad3 and iPhone5 couldn't connect to the wireless network but my wife's iPod, my friends nexus could easely connect to the router...
One thing comes up to mind: this is a hardware issue iPad3 & iPhone5. Plain and simple.
Going to the Apple Store on this one until I get and Iphone that works as promised...
I have tried everything including factory reset etc...to get wifi working again at more than two steps away from my router and on any hotspot.
I have one advise: dont waste your time, bring it back as must be an issue related to 6.0.2 and the hardware in that particular series of the Iphone5.
Thats what i have done and apple replaced it. I took them 3 weeks however to get me a new phone. It is a shame, especially when you know that it was only two weeks old.
The replacement is working fine, however the battery drains faster than the original one running 6.0.1