Do you need a newsletter component that can handle an unlimited number of newsletters with an unlimited number of subscribers?  One with most of the extra features you would want from an electronic newsletter, such as:

• attachment capability
• email address validation when registering
• sending a test email to an administrator admin before the entire list
• the ability to ban emails
• the option to embed images
• an automated unsubscribing link
• management of 'bounce' emails

All this would be no problem.