It can be useful to create a fake website that mimics the original website of the company you want to attack. If you are sending a fake press release by e-mail, it should redirect to the address of your bogus website. For example, if your target’s website is located at www.fancyrubbish.com, you could register a domain name with a very similar name, like www.fancyrubish.com or www.fancy-rubbish.com. The easiest thing to do would be to copy the HTML code of the original website and to upload it to your bogus domain. You would only need to edit the HTML code slightly to override the real content of the website with your own bogus content. If the original website contains a list of press releases, you could copy them all and add your own bogus press release to the list. You can easily mirror a whole website with tools such as wget or HTTtrack.
Registering a bogus domain name also allows you to create e-mail addresses that are very similar to your target’s official e-mail addresses. If your target sends e-mails using info@fancyrubbish.com, you could create info@fancy-rubbish.com. But this is not entirely needed since the SMTP protocol allows you to send e-mails from a forged address. (cfr. next paragraph)
Once again, be safe and register the domain name anonymously! It is easy to register it with a false name, but more difficult to pay anonymously: Paysafecard, Ukash are good solutions, even though not many domain providers support this payment method.