Please share any information that you have about converting widgets/gadgets from one platform to another.

I know there is a Google Gadgets to Dashboard converter, I wonder if there are others as well.

Here's another one: Convert any web widget to a Vista Sidebar widget.

Not sure how they cope with widget parameters though.

Amnesty Generator (the app kaintze mentions) is also available for the Mac and converts any web widget to a Dashboard widget. Like the Windows version, it's free and it's just a matter of copying and pasting widget embed code into it.

About The Versatile Unit Converter
The conventional unit converters provide a limited set of conversions, such as length, time, energy, etc. But what if you need to convert the consumption of your car from liters per 100 kilometers into gallons per mile? What if you would like to transform a wavelength into a frequency?

The Versatile Unit Converter manipulates units symbolically, and lets you enter whichever unit you need in the form of a mathematical formula. Other facilities, such as automatic conversion to systems of units (MKSA, CGS, atomic units, …) as well as special conversions (temperature/energy, mass/energy …) are also possible.

# Users can type in values and calculate exchange rates for any two currencies or metals they choose.
# Conversions are performed inline and in real-time for over 180 currencies and several metals. Tailor currency menus to your site’s traffic by selecting up to 10 favorites.
# Create up to 10 customized widgets to address various website requirements.