Round_angles for blocks

Hi please guys... guide me how to create roung angles for the block like here..www.student.bg

If you observed I need a little bit another type of round angles from the top of block only like here http://www.student.bg/

thx a lot Samie, waiting your answer

So they'll be the same size? cause the width of the image will be fixed ;(

ok.. and one more question how to make the block's backgr transparent? thx as on your site

what i shall write in the respective class in general.css

. example {

...??? ,,,??? - to be transparent?}