Barnes & Noble's Nook 1.3 software update makes the built-in Wi-Fi more usable: The company has finally enabled its promised "Read in Store" option, which connects a Nook automatically to Wi-Fi networks in Barnes & Noble locations, and allows owners to read an ebook in the store at no cost for up to an hour per day. (You can't choose among all ebooks, but some smaller set that's been made available from "more than 200 publishers" including all the major ones.) The feature is still in beta.
The company has also added a test version of a browser, which I imagine is primarily to let owners connect to Wi-Fi hotspots other than those run by Barnes & Noble. Even free locations often require a click to accept terms, or even an account for registration purposes. Boingo users and those with other accounts will be able to log in from a Nook this way as well.
The Nook includes 3G wireless, but when traveling outside coverage areas, inside in a place with weak reception, and outside the US mobile contract area, Wi-Fi will be a big help for getting material. It's unclear whether browser over 3G is included; Amazon allows browsing with an "experimental" tool in its Kindle hardware at no additional charge over 3G.