It depends on how you want to deploy your image. You can either create a DVD with your customized image and install manually (also known as Windows Setup), apply the image from a share using ImageX or deploy it using WDS.

See this article for steps on how to deploy your image.
See this article as a step-by-step on how to get started with Windows Deployment Services.

Regards,
Vit

Thanks for reading and posting your questions here.
Regarding Sysprep: if you install and customize an operating system and want to capture it as a .wim file so you can later deploy it, Sysprep prepares the installation so that you can create an image, the .wim file. An operating system includes some unique elements that cannot be copied over to new systems, and here is where sysprep helps us. It generalizes (deletes) these elements so that you can deploy the image to other computers. After the image is copied onto a destination computer, and you start the destination computer, a shortened version of the Windows Setup program runs. The shortened version of Setup configures only user-specific and computer-specific settings, such as computer name, domain membership, and regional options. You can automate this last part of the setup process by using an answer file, a simple text file that instructs the Setup program how to configure the various operating system settings.

Regarding you second question, as far as I know, deploying .wim files is not supported with RIS. Instead, you can use WDS. See here for details on how to get started with WDS http://technet.microsoft.com/en-us/library/dd744343(WS.10).aspx.