The official Sysprep utility is located in the folder c:\Windows\System32\Sysprep of the Windows Vista environment. There are some tips that I can give you to help in creating your image which might make it easier to move from the third party tools which you have outlined to the official Microsoft tool.
The first tip is to use Audit Mode to customize the system and perform customizations to the default profile. By allowing you to log into the system as Administrator, Audit Mode can significantly simplify the customization process. In order to customize the default profile in Windows Vista and Windows 7 you will need to make your customizations in Audit Mode, and then run Sysprep with an answer file which has the copyprofile setting enabled.
The second tip is to use the Windows Automated Installation Kit (Windows AIK) which includes several utilities which can help make using the official utility easier including the Windows System Image Manager (Windows SIM) which helps to make creating an answer file much, much easier and ImageX, the Microsoft cloning utility which creates file based images (.wim) allowing the images to be modified after their creation to apply updates, new drivers, or applications.
The recommendation by mr_smartepants is certainly a great recommendation as well. The Microsoft Deployment Toolkit (MDT) combines all of the official tools above into a single workbench interface which can help automate the entirety of the process. Additionally, it is compatible with Windows XP, Windows Vista, Windows 7, and Windows Server 2003, 2008, and 2008 R2, which means learning one utility to do all of your deployments. Furthermore, it is exceptionally useful in creating “universal” images as it can easily add or remove drivers or applications from the deployment images.