I am really looking for either a small code snippet, or a good tutorial on the subject.
I have a C# console app that I will use to somehow add list items to my custom l
I think these both blog post should help you solving your problem.
http://blog.the-dargans.co.uk/2007/04/programmatically-adding-items-to.html http://asadewa.wordpress.com/2007/11/19/adding-a-custom-content-type-specific-item-on-a-sharepoint-list/
Short walk through:
Add a new item to the list:
SPListItem newItem = list.AddItem();
To bind you new item to a content type you have to set the content type id for the new item:
newItem["ContentTypeId"] = ;
Set the fields specified within your content type.
Commit your changes:
newItem.Update();