you can only get rid of the delay completely by getting rid of the bootloader entirely.
To do this you just burn your sketch using an ISP programmer - this is a separate piece of hardware, and Ladyada sells an excellent one.
After you get rid of the bootloader you can no longer upload sketches directly using the serial port (the serial port can still be used for communication during sketches.)
You can re-burn the bootloader using the same ISP programmer from within the arduino IDE.
http://arduino.cc/en/Hacking/Programmer