I really can't envision how you would format a survey for email, and have it returned in a reliable way. I think you'd actually make it more difficult for the respondents than if you just sent a link to a web-based survey.
There are a number of fairly well-known web-based tools out there (Zoomerang, Web Monkey, Doodle, etc.) but you got me curious and I think if I was in your shoes I would give this a try:
You can download results as delimited text and use FileMaker to slice and dice them.
I really can't envision how you would format a survey for email, and have it returned in a reliable way.
That's a good point, and the link looks interesting. SurveyMonkey also have a free plan, for up to 10 questions and 100 responses. I mention this because I have seen some of their result data in the past and it was well thought out and easy to work with.