Since upgrading 'everything' today to deploy to OS4 devices, it no longer recognizes localized XIBs and plists. (It=neither iPhone simulator or iPhone.) As in, before OS4, switching language caused the correct localized files to be loaded, but not so now. Does something need to be 'recreated', 'nudged', or renamed? It has worked on simulator and devices since April, and I get no warnings in my code.
The languages are English and sv_SE, in case there has been a change in language codes.
I've been having the exact same problem, but now I'm starting to wonder if the old way of doing it was just "doing it wrong".
Either that, or NSLocalizedString is just broken.
After cleaning up the XCode Projects folder (general maintenance), it works. I also had other problems with XIBs. I had two folders with two versions of the 'same' xcode project in the XCode Projects folder. Likely at one point I had unzipped an older version to check something or copy code from, and that confuses XCode about which files are used, is my guess. Sorry about that.