Open the project in Eclipse.

Right-click the project node in the Package Explorer or Navigator.  Choose the Team->Share Project menu item to open the Share Project Wizard.

Choose Vault Professional as the repository type.

Enter your username, password, and server to login to Vault Professional.

Choose a repository.

Browse the contents of the selected repository and choose a destination folder.

The Share Project Wizard will have auto-pended an add/create for all the files and folders in your project (with the exception of those types that are specifically excluded by Vault Professional or Eclipse).  You can tell that these files and folders have a pended add because they will be decorated with an asterisk and a plus sign in the Package Explorer and Navigator.  The pended adds will also show up in the Pending Change Set View.  To complete the sharing process, open the Pending Change Set View and Commit All.