http://www.convertit.com/Go/ConvertIt/ - ConvertIt.com is the very best conversion site we've seen. They have conversions for measurements, currencies, time zones, geographic reference, and calculators of all kinds. There's conversions on this site for stuff that we didn't even know existed, folks. Have fun exploring.
http://www.unc.edu/~rowlett/units/index.html - How Many? is a quite extensive dictionary of the units of measurement. The listing is alphabetized, with a good description of each unit, along with cross-references for related topics.
http://www.legacysy.com/convert2/ - Legacy Systems Convert2 has an alphabetical list of convertable units, from acceleration to volume, allowing you to input a value to be converted from any unit of measurement within that category to any other. If you don't want to input a value, the site will simply tell you the conversion ratio. This is the one of the best conversion sites we've seen. Don't pass it up.
http://www.ex.ac.uk/cimt/dictunit/dictunit.htm - A Dictionary of Units provides a summary of most of the units of measurement to be found in use around the world today (and a few of historical interest), together with the appropriate conversion factors needed to change them into a 'standard' unit of the SI.
http://www.onlineconversion.com/ - Convert just about anything to anything else at Onlineconversion. They have over 8000 award winning conversions and calculators, including length, volume, weight, speed, temperature, time, cooking, angles, area, power, energy, density, force, and many more.
http://www.omnis.demon.co.uk/ - The FootRule is a continously expanding collection of converters, units and measures, data tables and facilities for the student or teacher, scientific or engineering worker, parent and child. The converters provide not only information such as "how many miles in a light year", the difference between US fluid and dry gallons, the differences between both these and the UK gallon, but also gives the invaluable background on units, their origin and definitions.
