Create HTML newsletter source from Wordpress

Is there a way to export certain posts into an HTML newsletter format that is suitable to email to subscribers?

I am thinking of something that allows me to select a certain amount of posts, etc and that then generates in-line HTML content with those posts in them in a format I can copy and paste into a newsletter management tool (i.e. mailchimp, campaigner, etc).

I've noticed that some mail providers like mailchimp, aweber, etc offers RSS to email, which looks pretty handy and might work - unfortunately my client is using campaigner.com which does not appear to offer this. Perhaps there is another straight forward way to generate an HTML email?