The pen tool is capable of creating practically any curved shape.
This tutorial is fairly lengthy but won't take you more than 30 minutes to read. It really starts getting to the nitty gritty at page 3 so I've given you the link to this page below.
Once you've created a 'path', simply go to your paintbrush, select your brush style, size, colour, drawing mode and opacity of your line. Then click the pen tool again, right click on the path and do Stroke path