conversion

Harold McGee has a useful conversion table in Keys to Good Cooking. He covers the basics like sugars, flours, rice, salt, butter, cream and such. Or buy a scale and developed your own recipes; that is what I did. Or use original sources from almost any European country or probably South America. That is called putting your liberal arts education in French or Italian or Spanish to good use.

I use this one all the time: http://www.metric-conversions.org/

http://www.exclusivelyfood.com.au/
has a great cup to gram conversion table of pretty much everything you can think of. They update it often and very reliable. I have it printed and placed in my recipe's folder.
The exact link to it is:
http://www.exclusivelyfood.com.au/2007/04/what-does-1-cup-of-weigh.html

http://www.onlineconversion.com/weight_volume_cooking.htm

Most conversion sites are fairly accurate. What are you wanting to convert cups into?