Here is a minimal example using the eso-pic package.

\documentclass{article}
\usepackage{eso-pic}% http://ctan.org/pkg/eso-pic
\usepackage{lipsum}% http://ctan.org/pkg/lipsum
\begin{document}
\AddToShipoutPictureBG*{%
\AtPageUpperLeft{%
\hspace{\paperwidth}%
\raisebox{-\baselineskip}{%
\makebox[0pt][r]{Here is some interesting text}
}}}%
\lipsum[1-3]
\end{document}
\AddToShipoutPictureBG will print something on every page, while the starred version \AddToShipoutPictureBG* prints it on the current page only. Placement is possible with spacing commands, with the help of predefined locations (like \AtPageUpperLeft and the like). See the package documentation for more on this.
eso-pic also provides placement of contents in the foreground to overlay with the existing page layout (in contrast to placing something in the background layer as suggested above) using \AddToShipoutPictureFG or \AddToShipoutPictureFG* with similar connotations as above.
eso-pic. And, I'm pretty sure bothpstricksandtikz/pkgwill be able to accommodate this. – Werner Oct 01 '11 at 21:27