If you're doing your own custom newsletter, great. If you're using a service with pre-written content, they probably allow you some area of the newsletter for customization. In either case, placing one sentence in the copy can begin the process of converting newsletter recipients to email or other online delivery methods. Something like "Help us to help the environment and save trees. Receive our latest real estate and area news in your email."
There aren't too many people out there that aren't concerned in some way with the environment. This appeals to them in that way, and shows them that you have the same concerns. It doesn't hurt either that it saves you the printing and postage costs! Using a service (can be free) to deliver the latest content from your blog will then provide really fresh news to your readers, while saving you time for design and mailing tasks. After the statement about switching, just give them a simple link to type in on your web site or blog to subscribe.

