How to set up a newsletter – not spam

I am looking for an easy way to send out a newsletter to our customers (about 200 at once). I want to be able to hide the addresses of other people on the list when the newsletter is sent.

Right now I am collecting email addresses into a Access database and then importing it to Outlook. From there I am sending about 100 emails a shot but the problem is that a bad email will screw up the whole process.

Any suggestions would be greatly appretiated.