Hi, I run a Lettings Agency in Cambridge: www.lettingsmatch.com (might as well get my free plug, they do it on Radio 5 all the time). I decided to give email marketing a go.
After trawling the net, I came accross www.livewirecampaign.co.uk
LiveWire Campaign gives you access to free email marketing and free email advertising to your clients and customers.
Basically there is no setup charge or monthly commitment. As far as I understand, the first 50 emails you send every month is free. So you can sign up now, create a email campaign or newsletter and email it off to your contacts or yourself as a test.
Plus they give you the facility to use templates, monitor emails you sent, how many people read it etc....
All in all, I was happy and thought I would share it with you. I also discovered a great way to find details of prospective Landlords, so my list of 0 has turned to almost 150 email addresses overnight.