OK this is long.
First create an rgp document, select the rounded rectangle in the shapes selection. Go into the tools options and makethe radius about 50px. Make sure you select create as filled region.
After you made the shape, select it and make a new layer out of it, this will be the base for the pic, select the gradiend tool and select dark blue and a lighter blue. Fill the shape darker color on top. Go into layer styles (layer effects for photoshop 5) then select drop shadow, angle 90°, opacity 30-40, distance 47, blur 20 and intensity 10. Then go back into layers styles/effects and select bevel and emboss. Highlight opacity 100%, shadow opacity 50% and make the shadows color burn. And the bevelling will be depth 5% and blur 12%. After thats all done make this layers opacity 75%.
your stuff should look something like this.

Duplicate this layer, blendin options multiply and opacity 30%. Give this layer a drop shadow, in the drop shadow options panel select the color a light blue instead of black, opacity 100%, distance 33 and blur 20.
With the selection intact create a new layer and fill it with white, press ctrl+d to deselect and then press ctrl+t to transform, make this layer smaller and put it in the bottom center of the original shape, this will show the glass like transparency of the button. Then go into Filters and Blur then select gaussian blur, radius 10 pixels. Then go into the layers palette and blending options, select ovarlay and then make this layer\'s transparency 40%. Now duplicate this layer and make it color dodge and transparency 10.
Now duplicate layer2 copy and resize it to be even smaller than the previous layer (this is done to add realism to the shading), put it into the middle of the layer and make the opacity 20%.
Now, create a new layer (layer 3), then hold ctrl and click on layer one (this will make the shape a selection again), select the gradient tool, under the gradient\'s tool\'s options select foreground to transparent. Fill the selection top to bottom. This will become the highlight like in my previous pic.
Create a new layer (layer 4) and repeat the previous to make the selection again. Go into edit and stroke, select width 2px and center for location. Press ok. For layer mode select color dodge and lower the opacity to 35%. Go into the Filter>>Blur>>Gaussian blur and enter 2px then click ok
Now you should have a basic aqua button, you don\'t have to use my exact numbers, play around with the numbers and colors to suit your needs.
Now to add text, press d to make the default color selection. Now press t to select the text tool. Enter some text. Now under the layer styles/effects select drop shadow. The color should be a medium blue and opacity 55%. Distance 8, blur 8 and intensity 0.
Now, most likely the finished result might look wierd to you, but that\'s because your still seeing the picture in different layers. A good thing to help this is make the pic smaller (ctrl+-)
The finished image should look something like this.

Now this was a rush job so it\'s not an exact replica, but you basically get the idea. And this is really difficult to explain without either a complete pictorial or you actually being in the room.