Amazon promised ebook loans back in late October, and today it looks as though they've finally delivered. And while Kindle loans have matched the excellence of Nook loans, the real shame is they haven't improved on the model.
A select number of "eligible" Kindle books can be loaned once, for a 14 day period, to anyone using Kindle software on any device. Eligibility is up to the publisher, and there doesn't appear to be an easy way to sort books by what's lendable and what isn't other than trial and error.
The process of loaning is terrifically simple; just press the "Loan this book" button and fill in the borrower's name, email address, and an optional personal message. They'll then have seven days to accept the loan, and once they've accepted it they'll have 14 days in which to read it before it disappears in a puff of smokey E-Ink.
For any gripes about the shortness of the two-week loan period and the tight-fistedness of publishers, it's still a great feature. With no overdue fees! [Amazon, thanks Scott!]