Staff and people are friendly and willing to help, unless you're asking for a crack for the software or just being a pain in the ass. You can find Rebirth songs, download MODs for Rebirth, samples for Recycle and buy stuff. All the essential Rebirth FAQs and links are list there too. Elektrisches Descent - A group of people from different places around the world gather to make quality music with Rebirth. Well worth the visit if you're around that area.
Music theory links - A page with a good number of music theory links.
From fundamental to more advanced. There is a tutorial on this site about The Polytonic Chord. I played some of the examples on the keyboard. You can hear what he's talking about. Interesting at the least.