If you’re planning on installing PC-BSD 7, or simply whant to know more about it, y strongly encourage you to read this review about it in OSnews.net. It will guide you thorough the whole installation process and post-install configuration, and will prevent you from make any typical mistake in the process, giving you very usefull tips to help you configure your computer for two or more operative systems.
If you’re interested in UNIX from a user point of view, PC-BSD is a very good option. Quoting the article linked above:
I am thoroughly convinced that PC-BSD is the perfect choice for a newcomer to the unix world. It is very straight forward and it requires very little unix knowledge. Even though I mentioned a couple of caveats (eg. bootloader, primary partition), I doubt a new user who is installing on a fresh system will ever come across these issues. Even if someone does run into these issues, the solutions provided in this article should give them a starting point. The PC-BSD has a friendly and helpful community, they have an active forum where you can seek help from fellow PC-BSD users. The PC-BSD team has worked really hard on this release and the results are impressive. It is ready to challenge the main stream Operating Systems (Windows, OS X and Linux). I would encourage new users to try PC-BSD without any doubts. I would definitely recommend Linux gurus to give this distribution a chance and I promise, you won’t be disappointed.
By the way, if you want to try this OS but can’t or don’t want to modify your existing partitions, you can use a virtual machine. In the official page you can find a VMware image so you can run it over your current OS.