Use the wrapfig package:
\documentclass[12pt]{article}
\usepackage[showframe]{geometry}% http://ctan.org/pkg/geometry
\usepackage{wrapfig}% http://ctan.org/pkg/wrapfig
\usepackage{xparse}% http://ctan.org/pkg/xparse
\usepackage{lipsum}% http://ctan.org/pkg/lipsum
\begin{document}
\NewDocumentCommand{\rtext}{O{1} O{5em} m}{%
\begin{wrapfigure}[#1]{r}[0pt]{#2}%
\begin{minipage}{#2}\raggedleft#3\end{minipage}%
\end{wrapfigure}%
}
\rtext[5][50pt]{Here is some right-aligned text}%
\lipsum[1]
\end{document}

The above code provides \rtext[<lines>][<width>]{<stuff>} that typesets <stuff> right-aligned (actually \raggedleft) in <lines> lines of width <width> (the default is 1 line with width 5em, although this can be changed). Both <lines> and <width> are optional arguments.
geometry was used with the option showframe to show the alignment of the text. lipsum provided dummy text, while xparse provides an easy means for specifying mixed optional/mandatory arguments (and defaults).
wrapfig? – cmhughes Oct 06 '11 at 21:23