Any vector editor will happily let you draw something like this.
Inkscape would be one free alternative.
Adobe Illustrator would be one expensive alternative.
In both, you would draw rectangles with grey outlines and white/green fill. On top of these rectangles, you would write the text you want to put there. Then, you either apply a drop shadow or put a faded black rectangle of the same size behind it to recreate the shadow effect.
You should be able to draw an Arrow shape to get the arrow. The long brace you would have to paint by hand using the line tool.
Alternatively, some flow-chart program could probably do this.
Check out Microsoft Visio for a commercial alternative.
Or take Dia as a free alternative.
Here, you would draw a rectangle shape with grey outline and white/green fill and a drop shadow. In those rectangles, you would put the desired text. Then, you would draw an Arrow shape to get the arrow and either use a pre-defined shape for the brace or use the line tool to recreate it.
A vector drawing program will give you more freedom to draw any shape you like, but you will probably have to do many things by hand--such as centering the text in the rectangles or drawing nice-looking braces.
A flow-chart program will provide you with handy templates for rectangles, braces, arrows and the like, but you probably won't be able to draw anything more artistic than flow-charts with it.