How can I allow creating content for anonymous/authenticated users without programming in orchard?

we couldn't grant the users this possibility without letting them access the admin panel and granting them the author permission.

What we want to achieve is just like any other CMS, create a content type, and let users create content based on that, but without accessing the administration panel.
we're not asking for a lot are we?

Orchard 1.5 will handle that scenario. In earlier versions it's not possible without building your own module.

While browsing the Orchard Gallery today, I saw this module <a href="http://gallery.orchardproject.net/List/Modules/Orchard.Module.uSubmit">uSubmit</a>.

It sounds like it handles what you need:
"Requires Orchard 1.4. This module provides a ContentType called UserSubmission for allowing anonymous visitors to submit content to your site. The content items that they can create include a title, an image, a story, and optionally their name, email address and tags. The story is entered with a Markdown editor, allowing them to provide a limited amount of formatting. The user submissions are saved as draft content and have to be published by an Orchard user (like the admin) with permissions to publish."

Hope this helps.