Here are some ways you can send email messages to your members:
Blind Carbon Copy
The simplest way is to use the blind carbon copy field in your email program. This involves cutting and pasting the addresses into the BCC field of your preferred email program. Be aware that most service providers have a limit on the number of emails you can send in a day (Gmail limits to 500 daily, for example). Also, you can be penalized for getting a large number of bounced emails when sending a bcc message, so it’s best to work from the cleanest list you can.
Importing a list into Outlook
Outlook lets you import an email list to send an email to. This uses your own internet service providers mail servers. Check with them for relevant limits and recommendations for email list sizes. Sometimes it’s better to split a 500 address list into two lists of 250. Your internet service provider should be able to inform you about relevant limitations and help you decide.
Merging to email through Word
In Microsoft Word you can merge a document directly to email. This is similar to importing a list into Outlook, but you’re using Word as your email editor instead of Outlook, letting you merge other data into the messages in addition to the email address. Like the Outlook option above, this also uses your own ISP.
Using an Email Marketing Service
Email marketing service companies like MagnetMail, ConstantContact, Blue Hornet, Aweber, and Mad Mimi let you host your email list with them and use their mail servers to send the messages out. They also often have customer service, tutorials, and newsletter and other message templates to help make the process easy and painless. These services may have restrictions on what types of lists you can use, and may inquire as to the business relationship between your organization and the contacts you are emailing.
To give you an idea on costs, here’s a web page with pricing for Constant Contact - http://www.constantcontact.com/email-marketing/pricing/index.jsp