draw your path using the pen tool. On the layers palette there is a slider for : FILL ; set it to 0%. Use the layer style : stroke to add the outline as you want. Like in AI you can chose from outside, center and inside strokes. you can even have patterned and gradient strokes.
Oh and remember there is no such thing as 'sharp' in onscreen bitmap. If you turn of anti-alias it will lok sharp AND blocky, especially if you zoom in. if you leave anti alias on it will look smooth (not blocky but slightly blurred when you zoom in. This is the nature of raster images.
hope that helps