Move VMware Server 2.0 Image to ESXi
I recently converted from a VMware Server environment to ESXi 4. For each VM, I ran the VMware Converter app and converted from VMware Server (the server 2.0 machine) to virtual (the ESXi machine). Worked great. The only wrinkle was that I had to reactivate each Windows machine. Apparently the "hardware" changed enough to trigger a new activation.
If for whatever reason you can't use the converter to move the machines there are a few ways to do this. First shutdown the guest and find it's data files on the VMware Server 2.0 machine.
You then need to copy those files to the ESXi server either through the Infrastructure Client (host->configuration->storage; right click the datastore and click browse) or through using SCP (eg WinSCP) and enabling SSH on the ESXi machine (http://www.yellow-bricks.com/2008/08/10/howto-esxi-and-ssh/).
Then import the machine by browsing to it's .vmx file in the datastore, right clicking and selecting add to inventory.
Hope these instructions work for VMware ESXi 4...