How are you doing that enhancing mate?
Dunno how to explain it, everything is just more vibrant and the slight shading at the top. Makes the photos awesome.
Cheers.
The "shading" at the top is called vignetting. It's actually an effect originally created in the lens, but these days it tends to be added later in Photoshop. It focusses the attention on the centre of the image.
The rest I'd guess is probably just tweeking the colours (hue and saturation), temperature, and white balance.