I have a dedicated server running Ubuntu 9.04 and I want to start doing virtualization with LVM. However I only have 1 partition for all my data on my disk and I need to resize it to have space for the LVM. Is there any way to do this remotely? My host can't provide KVM for me to boot with a live CD and arrange the partitions and I can't think of another way to do this.
I'm afraid it does sound like you need to go the KVM+Live CD route. There is no other option as far as I know. Your host really should be able to provide KVM access... they pretty-much all do, either for free, or charged.
Using .qcow2 image files is a reasonable way to do it though, you don't have to go the LVM route. If you are worried about performance, you can consider using "virtio" for the disk access, it's pretty good.
You do lose out on the LVM snapshots though. What I do is use a separate .qcow2 image for my home and var partitions, then that keeps the main OS on a really small .qcow2 file. I then have a script that pauses the VM, copies the main OS image, then resumes it. The copy takes about 30 seconds, so this is an acceptable amount of downtime for me, especially as I don't do this every day.