Just wondering if anyone is good with CSS ?

I've got a site with a background picture, on it I want to have a table with a transparant,white background. This will enable the text to be read without problems while still being able to view the background picture...

I've found this site :
http://www.mandarindesign.com/opacitycolor.html

but I dont know how to use the code there...

any help will be appreciated

-Mithrandir