have posted the same question some time ago. Unfortunately there is no way
to it. As many people desire this function it may be in the next release of
SPS.

The workflow capabilities of Microsoft Content Management Server are much
more enhanced and seem (if you have to believe the documentation) to be able
to do just this.....

I haven't tested it yet, but a whitepaper is available on
www.microsoft.com/cmserver <http://www.microsoft.com/cmserver> that shows
the integrated capabilities of using SharePoint and Content Management.

I posted a suggested solution on the USENET newsgroups. I haven't tried it
myself so no guarantees here. My idea was to create a Search Folder based on
a query that enumerates all rejected documents, then to subscribe to that
folder. When a document is rejected, it should show up in the folder which
would then trigger a suscription notification.

MS CMS has no notification  technology packaged with it other than going into
the workflow and checking. However there are event  sinks exposed in the web
interface that would allow you to programmaticaly generate notifications via
asp.

Does anyone know how to restrict de deletion of documents? or How to approve
the deletion? I think it should be a way to approve the deletion of
documents similar to the process of approving the publication

I do not know about approving a deletion but Microsoft has released web
part that will store deleted documents so that you can restore them. Look
at the sharepoint home page under the resource  kit tools.

I'll look for this web part and I´ll let you know if it works.