The content submission system isn't online yet. For now, just hold on to your content; we'll announce when it's ready. Web wizard and RimWorld expert Hypolite is the man with the PHP/SQL wand working on this.
Excellent. We'll be waiting :D
Indeed. High anticipation. :)
A test is currently ongoing: http://ludeon.com/forums/index.php?topic=1088.0
Check it out!