According to Reuters, the white iPhone 4 has been put off until around mid 2011. According to Boy Genius Report, it's been canned altogether. Who should we believe? Honestly, it doesn't really matter at this point.
One thing both sources agree on is that we're not going to hear another peep about the white iPhone 4 until next March. That's when Apple will either finally sell it, or push back the release date again until summer and quietly let it die. But with Apple releasing a new iPhone like clockwork every June/July, even if the iPhone 4 does hit the shelves it'll be old news - though appealingly discounted - in a matter of months.
Who would buy one then instead of just sticking it out for iPhone 5? And what incentive is there for Apple to crank on a lame duck device?