Mostly batik is used to make clothing fabric, with the use of repetitive patterns.
The procedure : melted wax is applied to cloth before being dipped in dye. It is common for people to use a mixture of beeswax and paraffin wax. The beeswax will hold to the fabric and the paraffin wax will allow cracking, which is a characteristic of batik. Wherever the wax has seeped through the fabric, the dye will not penetrate. Sometimes several colours are used, with a series of dyeing, drying and waxing steps.
Also see my blog post : http://wax-and-dye.blogspot.com/2010/11/to-explain-batik.html
In the traditional Javanese technique, wax lines are applied using a canting, a wooden handled tool with a tiny metal cup with a tiny spout, out of which the wax seeps.
For larger scaled productions, copper blocks are used to 'print' hot wax onto the cloth.
A good reference for traditional batik : http://batikindonesia.com/