First off all.. a question.. how do you manage your mp3's without a display.. Are they all stored in a gigantic playlist ???
No.. the schematics for a 4x20 and 4x40 are no the same.
4x40 uses a seconc enable line (e2) to enable the 2nd controller chip (44780)
One controller chip is good for 80 character.. therefore the 4x40 have 2 of these.
the 2 bars (1 and 3 ) on a 4x40 indicate that you have properly wired-up your display. It works..
Reason you don't get anything on the display is because you have to tell your pc to write data to the parallel port. (If you don't get any bars, check the contrast, and the wiring.. I've gone bezerk over my lcd not working.. checked wiring 6 times to find out in the end my contrast was zero, so nothing to read)
You can test this easily with a dos-proggie called LCDPRINT, do a search for it on google, and it show up.
It's a nice proggie where you select a text-file to be 'printed' on the lcd.
When you have tested this, and it all works out. (no garbage on lcd, otherwise check your wiring), then you can head on a search for some visual-plugins for winamp.
I recommend the Markus Zehnder Plugin because this one supports playlists, is easy configurable, and totally customizable (??spelling??)
You have to install these plugins into the winamp plugin directory and configure them..
If lcdprint like you wanted it to work, then you now should be able to view the mp3-tag information on your display !!!!
hope this helps you out !