NUS Downloader 1.5 Beta by WB3000
NUS Downloader, or NUSD, is a PC Utility designed to allow easy access to the resources present on Nintendo's Update Servers. Using this tool, you can download, pack, and decrypt many system titles into WADs ready to install.
CHANGELOG v1.5 beta
-Moved update database option to Extras menu, added ability to download database if none exists
-Added ability to download common key (via HackMii blog) if does not exist
-Added ability to accept hex STRING versions of the common key
-Made the database reading multi-threaded, so as not to delay GUI loading.
Source/Download:Downloads - nusdownloader - Project Hosting on Google Code