CUPS & GRAMS
There are lots of online conversion tools, such as this converter:
http://www.traditionaloven.com/conversions_of_measures/flour_volume_weight.html
and this chart of various cup meassurements in grams:
www.recipes4us.co.uk/us_cups_to_weight.htm
A few of the most common ones right here:
Flour and Icing Sugar
1 cup = 120g
3/4 = 85g
1/2 = 75g
1/3 = 40g
1/4 = 30g
Butter and Sugar
1 cup = 225g
3/4 = 170g
1/2 = 115g
1/3 = 75g
1/4 = 55g
Brown Sugar
1 cup = 200g
Yoghurt
1 cup = 225g