Humberto Adriano, I used to ask the same question to a lot of people on Flickr constantly, probably bugging them. There are a few options for Vignetting such as this. Option One (the one I chose) is to shoot Raw and in Camera Raw in Photoshop CS2 use the Lens tab and then select vignetting and drag it down to -100 or -75 or so. Option Two: Shoot .jpg and open it in Photoshop CS2 and use Burn tool at around 800 pixels and drag it evenly around the edges, and go back a 2nd time if needed. Option 3: Use the paintbrush at black coloring at hardness of 13 and evenly brush around edges.

Thank you Andrew! I'll keep trying with these advises!

Also, if you use Lightroom, there's a Lens Correction panel in the Develop Module. There's a vignetting tool there. I used it to add vignetting to this shot: http://www.zooomr.com/photos/maltphoto/3922309/

Thank you Andre! by the way that shot you attached is just great!