\documentclass{article}
\usepackage{soul}
\usepackage{color}
\begin{document}
\so{letterspacing}

\sodef\an{}{.4em}{1em plus1em}{2em plus .1em minus .1em}
\an{example}

\sodef\an{\bf}{.7em}{1em plus1em}{2em plus .1em minus .1em}
\an{bold example}

\caps{CAPITALS, Small Capitals}

\ul{underlining}

\st{overstriking}

\hl{highlighting}

\setulcolor{red}
\ul{red underlining}

\setstcolor{blue}
\st{blue overstriking}

\sethlcolor{green}
\hl{green highlighting}

\end{document}
