I include copy at the very top of the sale page that reads much like this: Thank you for subscribing to my article marketing newsletter (or requesting the free ebook "How to Article Market More Proficiently", whatever the case might be).
An email is being sent to your email address to confirm that we have your correct information, simply click on the link in the email and you will be directed to the download page (or other situation-appropriate page).
While you are waiting, take a moment and check out this incredible new resource that will aid you in your article-marketing efforts: And then at that point, the sales page begins.
Now, you could also have another backend sales offer after the confirmation in the confirmation email, and have the download link be sent to them in an email.
I choose not to do this because I am in the process of building relationship with them, and I feel that some people might feel that I am 'just trying to sell them something', which of course is true, but I might as well not be blatant about it.
The one upsell is enough for me, especially since I estimate that it converts at about 5% ( I don't have exact numbers on that one metric because I combine those sales numbers with others; remember I only track the sales from particular sources).