For a while now, Nintendo has been promising to allow Wii U and 3DS users to make eShop purchases from any web browser. But even though Nintendo has yet to show evidence that such a project is in the works, several inquisitive members of NeoGAF have done some investigating and discovered just such evidence: a page with the address eshop.nintendo.net. Best of all, it has been proven to be functional!
Here's what happens: Upon visiting the page, you'll see a button that will direct you to a code-entry screen. Clicking on that will take you to a login page, where you can sign in with your NNID and password, after which you'll finally be taken to the screen that asks you for a 16-character download code. If you happen to have a code for either a Wii U or 3DS game handy and redeem it here, the game will download automatically on the appropriate hardware! Several NeoGAF users have already confirmed that the games they redeemed have appeared on their machines.
Granted, this web eShop is extremely barebones at the moment, but at least it's an indication that Nintendo may have it ready to launch sooner rather than later.