[melvinram]

Constant Contact is the one I use and offer to my clients. The main reason is I personally get a higher delivery rate (instead of getting caught in spam filters) and their email creator wizard is awesome. Try out their 60-day free trial: http://email.volcanicmarketing.com

Other solutions out there are:

* iContact http://www.icontact.com - Their customer service sucked when I tried them out.

* Campaign Monitor http://www.campaignmonitor.com - I've heard good things about their reports but their delivery rates have not been as great as Constant Contact in my email campaigns.

* Exact Target http://www.exacttarget.com - Great for enterprise companies. They will cost at least $10k/year

* Vertical Response http://www.VerticalResponse.com

* SilverPOP http://www.silverpop.com Another enterprise solution with a big cost.

[johns]

Campaign Monitor and their companion product MailBuild http://www.mailbuild.com have worked great for me. MailBuild in particular is a fantastic web app and I have not had any issues with delivery rates. Both products also have an API.