When you have more than one Kindle on your account, there is a drop-down box and you can choose which Kindle you want to send something to when buying. If you look at your Manage Your Kindle page, your new K3 is probably already there and named something like "Buran's Kindle #2". You can rename your Kindles and use symbol characters such as a space, *, #, etc. to force the newest one to the top. All such characters are higher in the sort order than the letter "a".
Even if you ordered something and it got sent to the wrong Kindle by mistake, it will also show up on the other Kindle under your Archive. Provided that you have wireless on and are connected, clicking on the title in the Archive will download it to that Kindle. Or you can always just resend it to the other Kindle in Manage Your Kindle since any Kindles on the account can read any other books in the account.
Last edited by TomF; 08-13-2010 at 07:44 PM.
Reason: further clarification