I recently started to design my own patterns with Adobe Illustrator. I went through lots of tutorials on pattern design online and I want to share some links:
Repeating pattern design in Photoshop and Illustrator
Pattern Plugins for Illustrator
Creating patterns in Photoshop CS2
The Power (and ease) of Patterns in Illustrator

I already printed some of them, but the print quality wasn’t too good. Though I ordered some really good archival paper last week hoping I might achieve a better quality, because I’d really love to make some memo pockets with my own designs.