I saw a closed thread asking how to make seamless repeating patterns like you would see on real fabric and wallpaper and wanted to post a great tutorial resource for making real repeat patterns in Photoshop.
http://repeatpatterns.com/tutorial_photoshop.php
The tutorial shows how to make real repeating patterns, not simple tile repeats and you can make them using Photoshop alone without buying any plug-ins. There is also a repeat pattern tutorial in Illustrator:
http://repeatpatterns.com/tutorial_illustrator.php
You can even submit and sell the repeats you make on the same site.