Bended lines : help


Is there anyone out there that can explain to me how you make “bended lines” ?

I mean like these :

:: example 1

> the background lines

:: example 2

> below the menu, in the square box

Is there anyway to make these with Fireworks or Photoshop ?? Or does anyone have a tutorial on how to make these “bended lines”?

Thanks in advance

Pete Zahut