One of our clients emails thousands of newsletters to its customer base on a monthly basis. The process was running a little slow so we purchased EasyMail Objects 6.0 (http://www.quiksoftcorp.com/). This thing is lightning fast and can handle SMTP as well as access POP3 mail. It runs as a COM object.
The nice thing about this object is that it properly embeds the plain and HTML versions in the same message so you don't have to worry about whether the user is HTML-capable or not. If you're interested in using the object (they have a 15-day free demo you can downlad) you can grab the attached TCF file we built to use it. - James
EasyMailSMTP.tcf
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