I have a Kindle Keyboard and want to get a Paperwhite.  Can I have all my books on both readers at the same time, or are you only allowed to have a book on one Kindle at a time.

Yes you can have the same book on different Kindles/devices, as long as the devices are registered to the same account.

If both have wireless and it is turned on when you finish reading on one kindle, you can pick up the other kindle, turn on wireless to let it synch and go right to where you left off with the other.  One of the reading menu options is synch and check for new items.

Once you have both registered to the same Amazon account, you can go to the My Account menu, down to Manage Your Kindle.  Find a book, go to the Actions tab at the right of the book listing. Select Deliver To My, and then choose which one to download on.  If wireless is turned on, it will be sent to that kindle.  When you buy new books you can select which one to send to first, then use the preceeding method to get it to the second one.

On the Paperwhite, you'll find all of your books listed in Cloud tab at the top, and you can select and download from there.

Debbie, fantastic. Do come and let us know how you like it, when it arrives. I like mine so much, I am giving my keyboard to my mother.

I'll let you know how like it. I'm going to have a downstairs Kindle (where I don't need the light) and an upstairs bedroom Kindle so I can finally read in bed.

Cool!