Nintendo released a Wii Firmware update, version 4.1 today in Japan.
A bug fix to Wii Sports Resort, in which after playing a WiiWare/VC game off the SD card, and then playing Wii Sports Resort afterward, you would be forced to watch the how-to Wii Motion Plus video that normally plays only once on the initial play of Wii Sports Resort.
The usual warnings apply, updating is not recommended until more information is known about its effects on homebrew.
Bannerbomb is still working! You may check updates via Wiimposter Logs.
Version 4.1 of the System Menu was built on June 24th, 2009 and released on July 3rd, 2009.