I signed up to be notified months ago but learned today it's live now. So if you have only been at Amazon, you might was to stroll over. They don't require an ISBN (yet, I'm sure at some point everyone will) and it's an easy to navigate form.
Because of the formatting issues with Smashwords, I haven't used them for the last few books. There was a ton of information in the PubIt FAQ and I can only say it seemed that kindle style formatting would be acceptable at B&N. There's a similar preview and the document looked as good as I could expect.
If we listen to Joe Konrath (and we should) the sales away from Amazon are a fraction for him, which is another reason why I haven't been bothering with Smashwords. I don't want another afternoon spoiled by phone calls to my computer smart friend and struggling with obscure Unix commands trying to get the formatting right. It's not always easy to understand what the problem Word is having. Sometimes it's just easier to solve it in Open Office. Googling doesn't always give you a good answer.
Get your books to the reading public.