The 3DS firmware update adding the eShop, DSiWare transfer, web browser, and other features, was originally scheduled to be released in "late May." A note on Nintendo of Japan's website reveals that it's going to be released so late in May that it'll actually be June by the time it arrives.

June 7 is now the official date for the firmware update, in Japan at least. That happens to coincide with Nintendo's E3 presentation, so we're now expecting that to be the worldwide release date, so Nintendo can make a dramatic reveal on stage. We're checking with Nintendo, in any case.

[Thanks, Manuel!]