Create two textareas, one for create a form template and other for a mail template. The form can be putted in posts, pages or sidebars.
List of templates. See, your short tag is generated, you just need to Ctrl+c and Ctrl+v on yor post/tag.
Edit your form template.
Put your template form on your post.
You can change the reciver mail, passing the mail algument.
You can put the form on your templates, using the simple