I am helping someone write a how-to book on a subject, and we kind of need to use brand names in the process. Is this legal if I use a disclaimer stating who owns the copyright/trademark?
Brand names are covered by trademarks, not copyrights. If the use of a trademark is purely descriptive -- An "IBM PC" or a "Dell Laptop" -- and not used in any way that it implies sponsorship by the trademark holder or any other relationship with the trademark holder, then it is okay to use the trademark. Typically, you would make sure to add the "R" in a circle after any federally-registered mark, and "TM" after any mark that is not federally registered.
In addition, many larger companys will have a trademark usage policy on their corporate website -- if they do, that will tell you exactly how each trademark holder wants to see their mark used by someone else. Although the above rules will pretty much keep you in the clear, if a company has a usage policy, you should follow it to ensure you won't get into any trouble down the line.
