I've just spent the day re-writing an old adsense plugin so that instead of adding adsense ads into my posts I can use it to add my autoresponder html.
If you write a WordPress blog and would like to include your autoresponder form in any of your posts this tool will make it easy to do so. I use aweber and it integrates seamlessly into my posts.
This tool is ideal if you post previous issues of your newsletter on your blog and want add your “autoresponder form” to attract subscribers.
I'm not sure if anyone has released a plugin like this but i'm giving it away for free from my blog: karlwarren.com/blog