Allow Non Google Account to View/Edit Google Docs

Is there any way I can allow non-Google account to view/edit my Google Docs?

Note that I am not saying I want to allow everyone to edit/view the documents. I want only to allow people with a certain non-google email addresses to edit/view the documents.

Any idea how to do this?

From web app Ngu Soon Hui

• You can actually set view/edit permissions to any e-mail address by clicking the Share-button in the upper right but the persons who gets the permissions needs a Google account to use the document.

  Ngu Soon Hui : @eno, does this mean that I can only invite Google account to edit the document? Because if I invite a non-Google account, how does Google know what is his corresponding google account?

  neo : @Ngu Soon Hui: Google sends a link with an auth code. If you click on the link it asks you to log in (if you aren't). After you did this, the document is connected to your account (not sure whether it is possible to use this link again on another account).
  From neo