Originally Posted by Homercidal
Just make sure to use a parking page. Not using the domain name would be the first thing the internet cops look for if there is ever a debate over it's use.
If the parking page is going to do any good, it better be very specific to your business (not one of these generic, registrar-provided "This site is coming soon" pages), and it better not sit there for long. If an issue actually arises, you'll need to be able to demonstrate that you weren't squatting, which will require you to show that you were just holding the name while you got your business in order.
Re-reading the OP, I think maybe the question was a little more specific than some of the answers. When the time comes, if you want to establish a trademark (which is all that a beer name is), there's not a whole lot you need to do besides make consistent use of the term in business in a proper way, and notify anyone who you find using the name that you consider it yours. There are many other things you can and perhaps should do, but those are the fundamental things that establish the trademark as yours.
Really, though, there's not much sense worrying about the naming far in advance of establishing a business. A clever name isn't going to make or break the brewery. You do want to think ahead a little bit, but the more important thing to do initially is make sure that your clever name isn't already being used. That's a LOT more likely to be an issue than someone coming in and stealing your name before you have any market presence.
Note also that you will want to look at businesses other than just beer when picking names. In principle, a trademark is only valid in the area of business of the product. This is why Apple Computer and Apple Records could both exist (at least, until Apple Computer entered the music business). However, if the other trademark is well-enough known, you are opening a huge can of worms if you try to use it. If you tried to open an Apple Brewery and make Ol' Mac Lager as your chief product, that's not going to work.