You can make seamless texture in PS. Use filter - Other - Offset and enter this values in Horizontal and Vertical. For example if your ducument is 1600x1200px, you need to enter exactly half of horizontal size which is 800px and half of vertical size 600px, click OK. Now comes the tedious part, grab the clone stamp and blend the texture on horizontal and vertical center :)
Its much better if you look for tut., there are many on this subject. You`ll understand better if you can see the images :)

Tihomir

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