I've been doing an experiment with some squeeze pages and after sign up (which offers a free report) the page directs to an affiliate offer and the free report is sent via auto responder to their email. There are two downsides to this:
1) People think you've sent them to the wrong place.
2) They think the offer is just a pop up ad and close the window.
I've found that I can increase the take up rate of the offer I show them and reassure them they are meant to be on the page with a simple bit of HTML code. So now when they have opted in they see something like this: Demo opens in new window.
Here is the html source files that make it happen: Click Here to Download
Simply open the index.html in your preferred text editor and change the two links that go to my site to the affiliate link you want to promote, and then upload that and the thank_you.html file to a folder on your web space.
You can of course change the wording that appears by editing the thank_you file as well.
The only limitation of this is that some sites (not many) won't load in a frame. One example of this is the Warrior Forum, so you won't be able to load up a WSO using this.
Hope you find it useful.