1. How can I use Cyworld photo editor?
I wrote a mini guide here: http://sparkleapple.blogspot.com/2010/08/photo-on-korean-photo-editor.html
2. What photo editor program you usually use?
Adobe photoshop, though, in fact I rarely use PhotoOn editor.
3. What can I do with the editor?
Add cute templates to your selca, digitally put a frame, emoji, and make an animated gif as well.
So readers, I hope you will have a great time editing your pics （ ・∀・）
I'll be back with a better post ^-^ Ciaoooo~♥