Apple:

White models of Apple’s new iPhone® 4 have continued to be more challenging to manufacture than we originally expected, and as a result they will not be available until later this year. The availability of the more popular iPhone 4 black models is not affected.

Earlier this week Engadget reported on a story in 21st Century Business Herald that pointed out Lens Technology as the company responsible for the delays. Apparently Lens Technology is having problems with their screen-printing workshop and they’re only able to produce half of what Apple has ordered.

I’m sure they will get their production issues sorted out but I wouldn’t be surprised if Lens Technology is left off of the list of manufacturers for iPhone 5.