Pro Sites Get Started on Homepage

Hello,

Really simple question, but I can't figure it out.

I'm looking to make the main site of my multi-site installation work much like the edublogs.org or wordpress.com multi-site systems work, allowing for a domain selection, package selection, and check out.

How do I go about setting this up? I have all the plugins enabled and configured, but I can't find a shortcode to put on the homepage to facilitate this.

Any ideas?

Thanks!

Dan