Texture Workshop is a multifunctional toolbox which allows you to turn practically any picture into a repeatable tile very quickly and easily. Such tiles are used as backgrounds of webpages, as wallpapers, as textures for 3D objects and for many other purposes. The program can be used conveniently both by a beginner for creating the very first own home page and by a professional web designer for the large scale work. It can also effectively substitute the well known expensive, "heavy" and demanding experience graphic applications if you need to edit quickly your pictures of any kind. The unique feature of this toolbox is the "tilization procedure". You can take any picture with similar objects (leaves, stones, beans, nuts, bolts etc.) and with a single pressing a button process it so that the right area of the picture will imperceptibly flow into the left area and the lower area will flow into the upper one. In other words, a real repeatable tile will be obtained. The same can be done with a small fragment of a texture (marble, wood, water waves, tissue etc.) to produce a smooth and limitless surface.

Nice on-line tutorial