Good idea about the incentivizing.
To use aweber.com, I think you can only do it by:
1) getting the users from the “Newsletter” signup-form or
2) from a sign-up in your copy.
If you already have people register in Magento, you would likely need to pop the info into Aweber manually (whereby a “confirm?"-mail will be sent from Aweber at a time whenever you catch up with entering the names, which likely will be confusing for the users).
Then I think you’re better off by getting your visitors to really opt-in in order to get a coupon code or similar via the very first Aweber autoresponder message.
It’s simple enough to have the Aweber forms shown up in any copy on your page just by adding the piece of code you get from Aweber. It’s also not toooo difficult to make the aweber code show instead of the default Magento one. This is how I did it:
Locate the /app/design/frontend/default/default/template/newsletter/subscribe.phtml (or whatever your /default/default/ is) and change:
<form action="<?php echo $this->getUrl('newsletter/subscriber/new') ?>" method="post" id="newsletter-validate-detail">
<legend><?php echo $this->__('Newsletter') ?></legend>
<?php if( $message = $this->getErrorMessage() ): ?>
<p class="error"><?php echo $message ?></p>
<?php endif; ?>
<?php if( $message = $this->getSuccessMessage() ): ?>
<p class="success"><?php echo $message ?></p>
<?php endif; ?>
<label for="newsletter"><?php echo $this->__('Sign up for our newsletter:') ?></label>
<input name="email" type="text" id="newsletter" class="input-text required-entry validate-email" />
<button type="submit" class="button"><span><?php echo $this->__('Subscribe') ?></span></button>
into the code that you will get from Aweber (in what they call “in raw html format"), then you can actually preserve the Magento design by keeping the fieldset, legend, label categories like the ones above intact. You can even design the button design in the same way as above but by removing all “Magento PHP” and only stick the “Aweber HTML” into all those places.
A suggestion btw: Edit the subject of your thread into something like: “Aweber newsletter signup” instead of “Beginner Questions” since perhaps more may be needing something like the above.