Checkout this cool unit converter gadget with auto complete text box that I just submitted to Google. It understands input as mathematical expression involving any combination of units (i.e. m/s^2 to km/hour^2 etc.) so virtually any custom unit conversion can be done in a user friendly text box.
I will appreciate any feedback from the community.
Gadget location on Google:
Gadget location on my website is:
and
The web site is still in kind of developing mode. I want to create a users supported website where units and the units related information
can be added/deleted/edited by authorized users. As you would see, I have tried to tie any user input back to the given unit information
page where more reference information (Wikipedia etc) can be found. (Note: not all the unit information pages have been populated with reference information yet!)