There's a bit of messing around with these, but they're worth the effort. A quick trip to Chinatown will get you a mortar and pestle for $30 or $40. Make sure you get quite a big one and make sure it's the last thing that you buy- you don’t want to carry it around for hours.
Make a paste from the lemongrass, garlic, chilli and shallots in a mortar and pestle or food processor, adding a few drops of oil if necessary.
Transfer the paste to a bowl and add all ingredients except the chicken and mix well. Fold the chicken pieces through, covering them completely with the marinade, then cover and refrigerate for 2-4 hours
Thread the chicken onto wooden skewers that have soaked in water for a few hours and cook for a few minutes each side on a hot barbecue or grill