My iPodbay
 

Installed in a G3/300 Beige Tower
 
Here is a quick description of how I installed my iPod in my not so beige G3 tower. You could use a similar design on a B&W G3 or early G4. Have not even thought about a current G4.
 

   


Mount 2 wood block to a drive plate. Use foam strips to make a firm hold.
Fit another block between the two. This will set the depth the ipod will go.
Cut an opening for the cable. Leave extra room around the jack.
Make a cover out of whatever you have. Use spacers and foam to make a snug fit.
Use "JB Weld" or epoxy putty to set the cable. Use the ipod to allign.
Now I just pop in the ipod and sync it up! I used a large style zip bezel.
I added a light later. Just for kicks.
You can move blocks and top plate to get the right fit. Insert the iPod carfuly!