I just found that Apple has got an excellent list answering most common coding questions like how to tell is code running on iPhone or iPod touch?

http://developer.apple.com/iphone/gettingstarted/docs/gettingstartedfaq.action

I still hope there will be an official place for developers to discuss iPhone coding problems, like they’re doing in Adobe Labs, with forums and wikis. Currently some developers go to discussions.apple.com, which is not the best place IMO, because most people there are regular users, not developers, and discussion categories are defined for regular users too.