I agree with what mtec is saying.
By default Logic will save your projects here:
HD/*Your Home Folder*/Music/Logic/
When saving a project in Logic 8 or 9 you don't need to create a new folder for it, because Logic does this step for you. e.g.
Choose File > Save as..
Navigate to a location of your choice.
Enter the name of the project to be saved and Logic creates the folder with the same name in that location.
In the Finder if you look inside the folder, typically you'll see the logic project file, a folder called "Audio Files", a folder called "Project File Backups" and (if you have bounced any audio in your project) a folder called "Bounces".
Hope that helps