Funny enough I was just reading a recent article on forbes on this topic.  You can check it out here: http://blogs.forbes.com/marketshare/2011/01/23/why-the-news-release-is-worthless-in-todays-social-media-age/

I think that having a solid social network and using places like HARO, you are going to get a much better response for the effort you put in.  I think some of the cases where this can still be effective is when you have a really good newsworthy story (not a sales pitch) and an exceptional title that will not be jumped past by potential publishers.

As for a company to go to for pr's I have used prweb with good results in the past, but rarely use them anymore as we find HARO, MyBlogGuest, and building strong social networks to be far better performers.

Sorry for the delay in response, I didn't notice this until now.  Anyway, I think yolu are referring to Zemanta and Rand talked about it here: http://www.seomoz.org/blog/4-valuable-link-building-services