Here are some links to useful Internet resources for you:
Text Editors for Coding
http://www.bbedit.com – BBEdit is a great text editor for the Mac. Use it to code HTML and plain-text emails. Or check out their TextWrangler product, a lite, free version of BBedit.
http://www.notetab.com – NoteTab Pro is a great text editor for PC
http://www.macromedia.com/dreamweaver/ – You can use it to build HTML emails. Use the coding interface for HTML, but be careful of the WYSIWYG tool. It adds CSS and other things to your file (which you’ll need to take out for HTML email)
Graphic Design Programs
http://www.macromedia.com/software/fireworks/ – Great for designing anything for the Web
http://www.adobe.com/products/photoshop/ – A must-have for serious graphic designers. Bit overkill for HTML Email design, but you can’t list “graphic design programs” and not include Photoshop. Also check out Illustrator (http://www.adobe.com/products/illustrator/)
http://www.apple.com/downloads/dashboard/reference/picker.html – A great Apple Dashboard widget for quickly picking web safe colors to use in your emails.
http://www.vmware.com – You can use vmware to setup testing computers, with multiple operating systems and email applications.
http://www.hotemailtemplates.com – Tons and tons of templates for your email newsletters
http://www.glocksoft.com/ep/ – Nice tool for processing your "bouncebacks" and “unsubscribe” emails.
http://www.glocksoft.net/helpdesk/ – Our Help Center, with searchable knowledge base.