Know-How Exchange : E-Marketing

My company uses mailbuilder.com to send out our newsletters. We had some basic templates created for us in the beginning (2 years ago). I wanted to try to use one of their free templates in order to make our image a little more catchy. I understand I need to have an editing tool like Nvu to edit these. Does anyone have experience doing this? I have been looking at their website and see that people use it alot to creat web sites. I am looking specifically for help with newsletter templates and editing them. I have never done something like this, so it's all new to me. if anyone has any suggestions or experience with this and could share any info with me on how to do this, or experience with Nvu, I would appreciate it.
Thank you!