Hiding an affiliate link can be done in several ways:
1. Encrypt the link at Clickbank.com
2. Search for "cloak" in the Gold Vault. There are several there you can try.
3. Go to
http://www.wordpress.org and do a search. I've used "Go Codes" in the past successfully.
4. Purchase the CloakPiG plugin. It's one of the best paid plugins out there. Just do a Google search for a "deal".
Aweber code:
I've had mixed results with Aweber plugins. Best thing to do is grab the web form javascript code from your Aweber account. Just add it to your Wordpress page or post. WP can now parse javascript code properly.
Locking portions of a post:
One way I know to do this is with the paid plugin WP eMember. When the optin is submitted, your success page would be the post with the hidden content. When the subscriber is returned, they will need to login, but will be able to see the content since eMember will set the proper access permissions. This method is a little complex to set up, but works well. Perhaps some other can suggest simpler ways to protect content.
gary