You have SharePoint Forms Based Authentication setup using a SQL profile source. Based on some of the following articles.

http://support.microsoft.com/kb/952170

http://msdn.microsoft.com/en-us/library/ms998317.aspx

http://technet.microsoft.com/en-us/library/bb975136.aspx & http://technet.microsoft.com/en-us/library/bb975135.aspx

Now what? How do you get users into the database? Here are some of the ways you can manage users, roles and profiles for the SQL ASP.Net authentication provider.

Visual Studio ASP.NET Configuration

Open a website with Visual Studio and the Website menu will be available. If the website is SharePoint you may only be able to open a Local IIS web site or File System web site from the File->Open->Web Site menu as you will not be able to open a SharePoint site from FTP or Remote or Source Control.

FBA Image 1

CreateUserWizard ASP.Net Control

Open your SharePoint site in Designer 2007 and create a new ASPX file. Open the file in design view and drag a CreateUserControl from the Toolbox->ASP.NET Controls->Login onto the page. Save the ASPX page and browse to the new page. Enter values to create a new user and click "Create User" button. This will only work if FBA is already setup as it will use the membership provider set in the web.config file for the web application.

FBA Image 1

IIS7 Manager

In Windows Vista and Windows 2008 you can manage all of the users, roles and profile information right from the IIS manager GUI.

FBA Image 1

FBA Image 1

Membershipseeder tool from CodePlex.com

Link to newest release

I'm sure there are other ways to manage ASP.Net authentication provider users, roles and profiles, but these are the ones I know about and can recommend.