How to Restrict WordPress 3 Blog Posts to Admin Only?

I have a WordPress blog where us开发者_运维知识库ers can contribute articles and wiki entries (http://webypedia.com). The blog posts are normal post types. The articles and wiki entries are custom post types. I would like contributors to be able to add new articles and wiki entries, but leave the creation of new blog posts to Admin.

How do I create this kind of restriction?

Currently, out of the box, the contributor can create new post, article, and wiki.

You can change the capabilities of a role, with your own code or with a plugin. Remember to change the capability_type of your custom post types, otherwise you can't make a difference between a regular and a custom post.