newsletter code

Hi All, I have a question related to newsletter subscriptions to websites as well as sending out of the newsletters. Here is the scenario: Client wants a "subscribe to newsletter" dialog on website, typically just an email address. Then in his admin section he wants to send out HTML newsletters/plain text depending on the user's email client. Now how would I go about creating the newsletter in the backend? Using a WSIWIG editor? Or is there some code that you guys use as there are also things to consider such as: -bulk mailing, instead of sending many mails at once. Rather send out some scheduled emails -Plain text vs HTML email Etc... What do you guys use if you are building a custom web app? I have seen Webinsta before it works well but it's a separate system. Let me know, Thanks Kind regards Angelo Web: http://www.elemental.co.za