IlSilente ask me to do this tutorial (thi info maybe not true :P). We just explate how to create a reflection effect using The Gimp. Now let's see how to create a 2.0 button using the best open source (and not only) image editor.
First of all we heve to define what a 2.0 button is (almost in our concept). A 2.0 button is an image with 3D effect simulation and rounded corners. Have you a different idea? Maybe you are right, but this is my obsession :)
How To Procede
Open The GIMP and create a new image with transparent background and the dimension you prefere. By the "Select" menu, click on "Select All" (or type CTRL+A). By the same menu, click on "Rounded Rectangle" and apply it using the prefered ratio. I used the default value (50%).
The result should be something like this:
Using our prefer color, apply a background to the new selection.
Now create a new rounded selection (using the same ratio). It must be smaller than the first one and positioned at the top.
To this new selection, apply the gradient tool 
selecting the white color as SB and mantaining the previous FB. Drag the mouse from the bottom side of the selection to top.
Et voila! Add some text if you want. The final result is something like the image you can see at the begin of this post ;)
