1. Your site can be privately shared with a group of people or you can make your site public. In the "More actions" menu, click "Share this site".
2. Add the emails you want to invite. Remember that owners are able to invite others and manage the site, collaborators can edit content, and viewers can only read. You can "Choose from contacts" to see a list of your Google contacts. Click "Invite these people".
3. In the invitation dialog, you can customize the email's subject and message. Click "Send" to invite users, or click "Skip sending invitation" to add your named users without sending them an email invitation.
4. When you are finished adding users, click "Return to site".
Receiving a Google Site Invitation
1. If you have been invited to a Google Site, you will receive an email to the account that has been invited. Click on the link in the email.
2. In you are not automatically logged in or do not yet have a google account, Scroll to the site footer and click "Sign in".
3. Enter your google account email and password, and click "Sign in". If you don't have a google account you must first click "Sign up for Sites" (don't worry you can still use normal email). If you have a Google Apps Account click the "Sign in with a Google Apps Account" and enter in your Google Apps email address.
4. Fill in the Create an Account screen and click create. You are ready to enter your site.