I just checked the wordpress
Roles and Capabilities page, its a Contributor you should allow "somebody who can write and manage their own posts but cannot publish them", so you'd need to approve the post before it's published, even if they edit it later you still need to approve the edit.
If in zero you mean PR0, yes it still counts, but I was meaning you have no backlinks to your site. You need backlinks to your site to give it some authority and link juice flow, obviously the better quality links are best but PR0 links are better than no links.
Linkspun isn't 1 to 1 backlink trade, its ABCD, you need some sites to use for linking out and don't link out from your money sites. These links are still good, but you need to be careful what links you get as theres lots of shit on there like site-wide footer links with 100+ OBL's with no incoming links, these will definately give a negative effect.
Postkings.com also do ABCD links with contextual blog posts links that you write yourself on the other users blog, these are better links for ranking but theres not many members yet.
A good tactic it to use Linkspun for branded anchors to give your site authority and use Postkings for exact match keyword anchors for ranking.