Registering reduces the likelihood of spam entries in the database and will allow you to edit or delete the entries that you add. When you click register you will be e-mailed a link that will enable the Add a Resource link on the home-page.
NB. Outgoing messages use DKIM authentication but still appear to be blocked by some e-mail providers. If the e-mail doesn't arrive, check your Spam/Junk folder first, then use the Contact form and I'll manually e-mail a copy of the link.