The update relates to the Wii Shop, where you'll know notice that Wii Points have become Nintendo Points, to bring it in line with the launch of the Nintendo DSi and its new point system, that will allow users to download content onto their handheld. Points won't be transferable between the two consoles, but Nintendo obviously just wanted to avoid confusion by identically labelling the points scheme across both platforms.
There's also a minor aesthetic change with some new icons added to make sure you don't inadvertently purchase items from the shop when you didn't mean to. How very gentlemanly of them.
Included in the most recent titles for Nintendo's virtual console and WiiWare services are Tetris Party, a four player online version of Tetris. Incredible Maze, which is a maze game that sounds far from being 'incredible' and Gradius 2.