For more detail and download the software, you can go to Rainy's site. More information and manual here. It's an open source software and free.
I visited the Solwyvern's site. Then, I found a "Rainmeter" in library \ other section. It's Nanoha Rainmeter skin.
At your desktop screen, you'll see that you can measure CPU performance, network performance, disk drive, and even measuring Winamp!
But, I think that this interface is not enough be user-friendly..To set the main configuration of this software, you must create an .ini file, and configure it yourself by typing the code in the .ini file. Configuring skin is similar as setting the main configuration.
If you cannot, you just can download the skins from from Customize.org; http://customize.org/rainlendar, it depend on the skin / configuration. You will unzip file.zip then click 'My Computer' > 'Program Files' > 'Rainlendar 2' > 'Skins'.. You can put one folder which you unzip into the 'Skins'. Finally, you can open 'Rainmeter' and can choose which skin you like~