What should a press release look like and who to send them to?

Hello, I just launched one of my projects. It helps people write better by comparing their writing to a big database of pet peeves. Now I'd like to promote the site. I've heard some people suggest a press release. Is it spamming to write something up and send it to various bloggers/writing websites? Have you had any success with this approach? The website is http://www.polishmywriting.com/ if you're curious. Thanks. -- Raphael