Press Release Template available with structure and tips to help anyone write a press release. SEO wise most of these backlinks from a PR will be nofollow. Usually free press release distribution sites provide little exposure. In the past I’ve had some success with PR-Inside.com using a site such as pr.com
A lot of sites offer distribution services but often the distribution is poor and expensive. I had an account with a PR site but I suggest ya Avoid Bad Services and a year later I can tell you the article isn’t there so wasted time.
The impact from the last PR was positive and noteable. I stress though that the press release avenue shouldn’t be abused and needs to actually include newsworthy content. Posting a press release because you launched your site or hired someone isn’t newsworthy. Use the tool for distribution of something you’d read about another site.