I had an AT&T iPhone 4 but wanted to get locked into unlimited data on Verizon.
So on April 28, the day the white iPhone came out, I went to a local Best Buy at 10am but they didn't have the white iPhone in stock yet. The girl went to the back to check and see if they had come in but they hadn't. I decided to go ahead and get the black one. You can guess what happened next. As I was standing up to leave, a guy brought a box of white ones in. I asked the sales girl jokingly if could I switch but she said no.
Last Thursday night, I went to the Apple Store and saw the white and immediately decided that I had to have it. My mind was racing as to how I was going to make this happen. I ended up seeing on the web that night a memo from Best Buy saying that if you had purchased a black iPhone and were still within the return period(14 days), you could bring it in and exchange it for a white one.
The next day that's exactly what I did. I even decided to get the 32gb version because I figured that the extra space might come in handy. After paying an additional $107, I was out of there.