Shaykh Muhammad Ali Farkushafidhahullaah has calculated the weight-equivalent for 1 Saa' of various foodstuffs. The table from his [url=http://www.ferkous.net/eng/Zakat_fitr.php]website[/url] is given below.
The measures of Zakat Al-Fitr (in grams)
Semolina - 2000 Raisin - 1640 Flour - 1400 Couscous - 1800 Lentil - 2100 Couscous with big grains - 2000 Bean - 2060 Date - 1800 Crushed pea - 2240 Chickpea - 2000 Wheat - 2040 Rice - 2300
Below threads also have beneficial explanations of 1 Saa':-
[url=http://salafitalk.net/st/viewmessages.cfm?Forum=24&Topic=10187]1 Saa' according to Commission of Senior Scholars & Table of Measuring Units[/url]