No FreeBSD support planned anytime soon, which means no for all of 2004, currently. I'd like to explain a little more about what you want to do in the following paragraphs, but I don't want you to take the explanation for optimism with regard to your goal. I don't think you'll get VTune for Linux to run on FreeBSD even if you could successfully compile a sampling driver on a FreeBSD system --> read on.
The VTune for Linux (vtl) software comes with the VTune Performance Analyzer Driver Kit which is designed to let you compile a sampling driver for currently unsupported kernels on top of otherwise supported, released, default distributions. (You might even be able to successfully compile a sampling driver for a FreeBSD kernel --> presumably based on source from kernel.org, but that doesn't mean vtl will work.)
In fact, vtl is designed to work with specific Red Hat and SuSE distributions, and is intimately linked with not only those specific kernels, but various other libraries as well, including glib, glibc, glibc++, and others. We test just those supported environments during development, of course.
If you examine the release notes, you can see precisely what's supported and needed: but I think your chances of success would not be high pushing into the FreeBSD world. I wish I had better news, but I don't want you spending your time under the assumption there's a strong likelihood you'll succeed: I would guess the opposite, that there's a strong likelihood you WON'T succeed.
Any chance you can kick the tires on the software on a Red Hat or SuSE server in the meanwhile, to collect some performance data that way?