There are a number of online PR services that you can now use to help promote your UK business online. These PR websites charge on a per press release basis and also on the level of service that you desire. The service level reflects the PR distribution level and the quality of the Press Release feedback that they provide to you.
PRweb is one such online PR agency but there are many others. Across the variety of online PR companies prices range from free to a few hundred pounds per Press Release.
An online press release is written in pretty much the same way you would write a conventional press release article -
Headline, summary, release date, content (including the quotes from the various parties), contact info and then the "about" sections.
However, additional constraints are placed on online PR and these take the form of html restrictions as well as the number of links in the Press Release article.