That's where DeployStudio comes in handy. This freeware tool can be used to create deployment files using Netboot, external USB or FireWire drives, or any AFP, SMB, or NFS sharepoint on the network.
DeployStudio works with Mac OS X 10.4.11 to 10.5.3 at this point, and is updated regularly to include new OS versions. The package consists of DeployStudio Server, DeployStudio Assistant, DeployStudio Admin, and diffPackageMaker.
DeployStudio Server creates a network based deployment server containing the images. Assistant is used to configure the server and to create the NetInstall sets, while Admin is used to monitor deployments, manage disk images and scripts, enter configurations, and more. diffPackageMaker can look at the difference between two file system snapshots and create installation packages based on what has been changed or added.
Detailed documentation PDFs and screencasts are available on the DeployStudio site.