I haven't really done much of this in the past, basically because the subject matter of most of my sites didn't really tend to PRs very well. But I now have a new site that I won't mention yet that is lends itself very well to PRs.
I've done my research and it's probably best said like this "Don't write your own
PR" b/c you will always been biased towards your site even though you think your not "intentionally" trying to be over favorfull with it. Find a company or a freelance person to write a
PR on a subject of your choice, and influence that writer on how you want the
PR to read and allow them to place a mention of your site somewhere in the
PR where it doesn't seem like spam.
The news sources that pickup these PRs will not pick a
PR that to much promotion in it, they want a story and good one.
On the distribution side of things I have used prweb.com in the past and I really have no recco of them being good or bad b/c I haven't used it that much but they do have an 80 dollar option that everyone seems to think is the best.
Please give us your tips on PRs.