Here it is folks! You can get iPhone OS 3.0 immediately, as of now, this very moment, ahora mismo, from iTunes. Not sure how to do it? Open iTunes, making sure your iPhone is connected to your comp. Click your iPhone/iPod Touch's icon on the left.
Then just click the "Check for Update" button.
iTunes will let you know 3.0 is available - grab it. Then just do as it says to continue upgrading.
NOTE: If youo're not seeing it yet in iTunes, grab it from the following download links:
iPhone 1G - Download
iPhone 3G - Download