The Peek is like a BlackBerry without the phone. It's built for one function only: e-mail. And right now, Amazon is offering a pretty sweet two-for-one deal: Buy one Peek for $79.99 and get a second one free.
Keep in mind that you'll have to pay $19.95 per month, per unit, for service, but at least there's no contract; you can cancel anytime you want. Doing so would leave you with a fairly useless chunk of hardware--two chunks, actually--but there you go.
Actually, that's a big part of the Peek's appeal. Another is that it's way cheaper than most smartphones for folks who just want e-mail on the go (and even around the house). Plus, it's significantly less complicated than, say, a BlackBerry.
As with Netbooks, people just seem to love this thing--logic be damned! The twofer deal probably won't last long, so if you want in, act fast.