This is how you get the 3D look using channels. By creating a bump map and transfering it to an alpha channel, unexpected results can follow.
Create
text on new layer 1. and rasterize - PC right click on name in layers pallette/Mac-Cmd
Click >rasterize
Make new
layer 2. and using rectangular marquee tool make a box around the text.
Deselect - Cmd/Ctrl +D
Fill the
new box with white.
While layer 2 still active, Ctrl/Cmd click on layer 1 thumbnail.
press
del, should look like this
hide layer 1 and Ctrl/Cmd
click on layer 2.This is the image we are going to make 3d.
You could start at this point with any image as long as it is on a layer and filled with white.

Click on the new channel
button in the Channels Pallete. Alpha 1 will apper. fill your selection
with white, it should resemble the image shown.
Deselct and go to
Filters>Blur>Gaussian blur. The higher you make the blur the more
your image will be bevelled.
Click on the rgb channel at the to of the pallette.
Go back
to the layers pallete and select your image layer
Here is where the magic happens. Filter>Render>Lighting effects.
Use the settings here or play around with your own.
Click on texture channel and load Alpha 1. I deselected the white it high for this example.
Click on the color picker to give your light some color. We used purple.
Click ok and say
"wow."
The finished result.
I put a drop shadow and a blue gradient in the background for coolness
sake.
For more cool techniques like this
on an easy to follow video format check out Photoshop Secrets Special FX photoshopCD.com