Cons to Frames
Frames are simply asking for trouble. Older browsers have problems with pages that have frames and printing them can be annoying as is bookmarking them. Some search engines including google even have a hard time reading pages with frames. Frames also seem like amatuer work and look bad in almost anyway you use it. There are exceptions of course but good luck finding one. Simply put, don't use frames unless you think you've mastered the art of framing.