The fee to announce a site is $495.00 - Specifics and payment methods are described here
The URLwire FAQ (Frequently Asked Questions) can be found here. It's located on the 
URLwire homepage below the first screen, so it's easy to miss if you don't scroll.

You have several choices, all free.

Private Email
The private one-to-one email version is matched by me personally to your interests.  URLwire by email is not automated. I will only send the email version to people who ask for it. You tell me the types of sites you want to know about, and you only hear from me when I have a match.  This option is especially appealing if you only care about specific subjects.  For example, if you are a librarian at a law school, you may only care about legal sites.  If you are the family editor at About.com, you may only want to hear about sites in that topic.  To subscribe this way, send email to eric@urlwire.com and let me know what your interests are.