I am producing a number (50) of customzed PCs and I would like to add
some additional indicator lights to the front of the PC case. I would
like to figure out an easy and professional looking way to power and
control the LEDs using a standard mother board and any additional
commercially available PC boards.  One possible way would be to use a
controller board that would read in serial data from the serial port
on the PC and then turn on/off the LEDs based on those instructions. I
would like any sources for these PC boards as well as the information
for the programming interface.  Thank you.

Wow, did I have fun with THIS one!

There's just SO much stuff out there, I hesitate to point to just one.
My recommendation is that you surf around the sites I'll list at the
end of this answer, and spend a few DAYS deciding which of the cool
things you want to go with. However, to comply with your request, I
have a specific answer to your question. (This thing is neat)

Matrix Orbital has a cool product called the PC Drive Bay Insert.
http://www.matrixorbital.com/products/blk202a.htm

It's a LCD Display with Keypad Interface - 20 characters x 2 lines,
Six general purpose outputs (which can be used to power and control 5V
LED's)


Additional Links:

Reviews of the LK202
http://www.hitechmods.com/reviews/LCD/BLK202A-4BR/BLK202a.shtml
http://bit-tech.net/article/29/
http://www.virtual-hideout.net/reviews/mo_blk202a_4br_lcd/index.shtml

Specifications for LK202's LCD panel communication.
http://www.matrixorbital.com/manuals/lk20225/index.htm

PimpedOutCases (Check out the Reviews for a lot of ideas)
http://www.pimpedoutcases.net/

HiTechMods has some cool LED's (No controllers though)
http://www.hitechmods.com/reviews/lights/lights.shtml

(I personally like this one)
http://www.hitechmods.com/reviews/lights/el_badge/el_badge.shtml


Search Strategy:

Custom Cases
://www.google.com/search?sourceid=navclient&querytime=Fx2WjB&q=custom+cases

Ther are also companies that make PCI general purpose digital I/O
boards. These usually have dozens of lines and can be used with
optical isolated modules (e.g. http://www,opto22.com) to control 110
VAC power. But you would not need these to control LEDs. Here is one
example: http://www.aberdeeninc.com/abcatg/DAQ142.htm

The Opto22 site has lots more options and ideas. They also provide
software.

agr

It is possible to light an LED directly from the parallel port on a
PC, I've done it.  This would give you 8 LED's (for the 8 data pins),
and up to four others (for the strobe, printer select, etc.)  The port
should be able to power the LED as long as you hooked up an
appropriate resistor to each LED.  (An LED has a fixed voltage it
draws, and the amperage controls the brightness.  Too high a resistor
value would make the LED too dim, and too low may wreck the LED and/or
printer port.  Usually about 100 Ohms is right for a 5V signal like
this.)

Advantage:
  1. This is the simplest way to hook up extra LED's.
  2. The PC hardware maintains the values sent to the printer port
until something else is sent.

Disadvantages:
  1. It may be difficult to connect to the port if it's on the back of
the case (like a standard ATX motherboard).
  2. The port could be used for printing (because if the printer
select pin is off, the printer ignores everything sent to it), but
while the user is sending things to the printer the LED's would flash
randomly.
  3. Software, such as windows, may try to write to the port thus
destroying any message you currently have displayed.

Perhaps a latch (i.e. a 74LS75 chip or equivalent) could overcome the
last problems, but this defeats the simplicity of the idea.  (A friend
of mine once sold a very simple circuit which flashed LED's in this
manner for $20!)

Info on the printer port:
http://www.beyondlogic.org/