These two clauses mean basically the same thing: the reader or listener is being informed of something. The verb note in your first example is used in the sense of "take notice of." Similarly, be advised means "be informed or apprised." In both cases, the speaker or writer communicates a fact or situation. The difference lies in the level of language: be advised that is rather formal and is often encountered in commercial and legal contexts, while please note that is more informal.