You don't need a special application to download games or programs for your mobile. You can download them via your mobile browser from plenty specialized web pages. A similar application like Nokia PC Suite is Samsung PC Studio which allows you to easily manage the files in your Samsung mobile. Also you can import and export files (pictures, music, phonebook) to your computer or you can modify different multimedia files with the Multimedia Manager option.
Another similar application is Kies which allows you to transfer music, contacts and photos or update the firmware. Also you can add and edit mobile contacts, sync contacts with those of your mail client, manage your music and make playlists.