http://www.youtube.com/watch?v=XHjIhzbo8QE
video explonation
1] new document 500X500 px
2] select elliptical marquee tool, then hold shift and draw a circle
3] create a new layer and fill it with baby blue color
4] goto select>modify>contract by 5
5] create a new layer and select gradient tool
6] make the gradient from the the baby blue color (the one you used before) to a navy blue color
7] fill the selection from up to down
8] create a new layer, select the elliptical marquee tool and while pressing alt, deselect most of the circle, just leave a smilly like selection on the botom
9] than goto select>feather by 15
10] fill the feathered selection with sky blue color
11] create a new layer and use the elliptical marquee tool to make a oval on the top part of the orb
12] select the gradient tool and fill the selection with white to transperent
13] set the opacity to 90% and add a filter>blur>gaussian blur
to 0.5
14] delete the background
15] good luck
tell me wht u think
Thank you for your contribution! 
Please have a look at the rules. I will edit your avatar for you now though. I don't feel it's very appropriate for the forum. 
Well not sure if you where after that of course! 
and also useful. But i do near the same in Adobe Illustrator. I'lll upload one soon if i get to that compu. where i made them 
