Ben Armstrong (aka "The VirtualPC Guy") has posted an interesting article detailing how to set up a virtual machine of Windows Vista with BitLocker enabled. Ben is a program manager on the core virtualisation team at Microsoft so as you'd expect the article very well written.
If you want to set BitLocker up in a lab and really don't have a spare machine then this approach may give you what you need to justify getting hold of a machine to take things further. As I've mentioned many times before you can use BitLocker to encrypt partitions on your hard disk without the need for a Trusted Platform Module (TPM) v1.2. Without the TPM you won't be able to generate/store the keys in hardware nor will you be able to take advantage of the secure startup functionality which checks the integrity of the boot files.
Don't be tempted to use BitLocker on virtual machines to mitigate threats though as I can't see any way in which this approach would increase your security - Ben's not claiming this either.