Usually with most press release sites you have to login and create a new account. When submitting a press release make sure it is well written with important info on what your website, products or services is about. Keep it clean of a bunch of links and don't make the press release to long. You want to keep the reader engaged with useful relevant information that will drive them to your pages.
Here is a list of Press release sites that can drive a huge amount of targeted traffic to your site: