All you need is:
2 Altoids tins
2 push buttons (1 has to be rated for at lease 3 Amps)
Now unfortunately I do not have picture of me making the above coil gun; but i did make a quick example circuit to show the step by step process.
Step 1: Inside of the Camera
Take the camera out of its plastic container. you can remove the extra metal wings ( they where mechanical contacts) we don't need them anymore). You should also remove the flash (unless you want it to flash as you fire the coil). Last remove the capacitor; you might want to note which side is negative on the PCB.
Step 2: Charging Button
Extend the button out.
Please note that as this is for demonstration purposes you may want to extend yours further.
Now you can throw out the capacitor; use more capacitors for a stronger magnetic field. Just remember to keep the capacitors in parallel; you also have to keep all additional capacitors at 330 volt and as photo-flash capacitors; you can have varying farads.
Step 4: The LED
Now its time to pull out the LED; take your time in desodering, and remember the position of the leads.
Step 5: The Fire Button
Now take you firing and connect one end to the positive side of the resistor
Step 6: Coil
Next use that pen tube and start to wrap with the magnet wire; I suggest using a 20-22 AWG and making at least 3 wraps.
remember the neater the coil and the more wraps you have equal a stranger magnetic field.
Step 7: Final Connection
Now connect one end of the coil to the capacitor and the other to the button
Step 8: Closing Remarks
I am surprised at how may people think I can kill with this; my capacitor bank totals 480uF and my coil is warped 5 times to fitt my alltoid form factor. My estimation is that you need at least 1000uF and 15 wraps on the coil. I shoot my coil at people and they don't even realize it it's so week; just don't point in at an eye.
Also remember to scale everything you see in the pictures up; and that you can use any farad of capacitor as long as it is rated and 330 Volts and for photo-flash.