This is something I've been looking into for a while.
power Convert by PlateSpin is the most automated way to go but, it ends up costing about $800 per server. It just works. With every other product, you have to go in and manually configure the VM's IP address. PowerConvert leaves the VM ready to go. You can even customize which services get stopped when the VM is created and which services are disabled in the VM. There was an issue a while back with scheduled P2V's but that's been fixed. if you've got the money, this is the way to go.
I've seen ESX Replicator but, it's not licensed by CPU like the rest of their products. I believe it ends up costing about $400 per VM. There's a bundle you can buy for $499 per CPU and it comes with ESxranger, ESX Charter, and 2 licenses for ESX Replicator.
Vmware converter works but, there's no way to schedule a P2V. Even if there is, you've still got to go in and mess around with the IP address and stuff to get it to go.
Acronis True image allows you to create an image and, with their $199 universal restore option, restore it to a VM. Sort of like a P2V. It works. Acronis True Image is about $499 per server. It's unclear if you have to buy the Universal Restore option for each server or not. While the creation of the image is automated, the restore to a VM is not. You can create a BartPE boot disk with True Image on it to boot the VM and restore the image but, the Universal Restore option is not available with the BartPE plugin they provide. At least not as of a few month ago when I was testing this. They are currently working on their own scheduled P2V tool. It was supposed to be released in June but has gotten held up. i'm sure that will be expensive too.
Until I ran into the lack of Universal Restore with the BartPE version of True Image, here's what my plan was:
Use Acronis True Image to create a nightly image of a physical server.
Create a custom BartPE CD that will boot a generic VM, map a drive to a share then, restore the image using Universal Restore.
I'd have a seperate BartPE boot CD (ISO) for each server i wanted to do.
I'd have the scheduler in Virtual Center just boot the VM each night from the CD.
It seemed easy enough. Everything worked but, without the Universal Restore feature, the VM would blue-screen.
In a pinch, that may be all you need. The question is, how "hot" do you need your VM version of each physical machine? If the VM has to be up and running on a moment's notice then, the above won't work for you. But, if you can spend about 20 minutes getting rid of the blue-screen, it might be just the thing.
You can use the Ultimate P2V tool to get rid of the blue-screen about 90% of the time.
http://www.rtfm-ed.co.uk/?page_id=174
To take it a step further, i wanted to see if i could do it for free.
Here are two free imaging tools I've used:
http://selfimage.excelcia.org/
http://www.runtime.org/dixml.htm
It's been a while but as i recall, one of them does not support scripted restores.
The plan was to schedule a nightly image as before but, instead of booting off the True Image BartPE CD, I'd incorporate one of these imaging products into the Ultimate P2V CD. The problem I ran into was that you'd have to boot once to restore the image then, boot a second time to fix the blue-screen. I'm sure it could be done somehow but, i just ran out of time. The other option is to use scripting with Vmware and mount the image restore CD, restore the image, then mount the ultimate P2V CD and boot.
Wow, that was a long post but, I'd like to have a hot spare of ever physical machine too. Why not? It would be free. You don't have to pay for the OS because it's turned off. And technically, you wouldn't even have to pay for a copy of ESX until you actually turned on the VM.
