Eat3D has got a new tutorial available for your educational benefit. The topic is...
Tileable textures in Zbrush.This is a wee bit more than just using offset in PShop. Jump over to their site for the sights but if you need more convincing;
In this demonstration, Andy Davies goes over the creation of tileable textures within Zbrush 4.
He shows the techniques needed to efficiently create a realistic rubble pile by making a tileable ground mesh using Displacment maps and placing premade Polypainted assets whilst offsetting the canvas.
He then shows how to create and export the Diffuse, Displacement, Normal and Ambient Occlusion maps from within Zbrush, along with the final tileable rubble mesh for use within xNormal for an additional Ambient Occlusion bake and any other textures that may be required.
Check it out here: http://eat3d.com/free/zbrush_tile