I just p2ved a 2008 R2 with GPT-disks and EFI-bios to ESXi 5 .
Procedure is quite straight forward ....
1. boot source machine into Ubuntu 11.04 64bit LiveCD
2. attach large USB-drive or networkshare
3. dd if=/dev/sda of=/mnt/import-flat.vmdk
4. create import.vmdk
5. upload import.vmdk and import-flat.vmdk to new directory on ESXi
6. create new VM with LSI-SAS
7. add firmware = "efi" to vmx
8. start VM into 2k8-64 recovery CD
9. enable LSI-SAS to start at boot
Just a minor comment on pt.6:
Don't forget to create the VM as the same acrhitecture as the source (32 vs 64bit) because the EFi nvram file is different.