Bozza, if your pork belly is already in strips (I believe supermarkets sell in that way called 'streaky pork'), colditz's recipe works well. You can marinade the pork belly in a mixture of 4 tbsp soy sauce, 1 tbsp of water, 1 tsp sugar and 3 tbsp of rice wine/sherry and leave it to slow roast in it, together with (optional) broken up cinnamon sticks, star anise, chopped ginger. I always put a little chopped bird's eye chillis as well, but I like spice with my food.
If your pork belly is in a slab (you get that from a butchers), Rick Stein's crisp Chinese roast pork recipe is fab.
Recipe is for a 1.5 kg/3 lb slab:
Spike the skin of the pork many times with a skewer or needle, going through the fat but not into the fat.
Pour a kettle of hot water over the skin, then drain and pat dry.
Fry up until aromatic 1 tbsp Sichuan peppercorns and 1 tbsp black peppercorns - or just use 2 tbsp black peppercorns. Grind to a fine powder. Stir in 2 tbsp sea salt flakes (or just normal salt), 2 tsp five-spice powder and 2 tsp caster sugar.
Turn pork flesh side up on tray and rub flesh with spice mixture. Leave aside cool for 8 hours or overnight.
Pre-heated 200 degree oven. Turn pork skin-side up on rack resting on roasting tin of water. Roast for 15 mins, then lower temp to 180 degrees and roast for a further 2 hours, topping up water where necessary.
Increase to 230 degrees and roast for a further 15 mins. This is to crisp up the skin for serious crackling.
Cut into bitesized pieces and serve warm.