xetex-letter.tex

\documentclass{xetex-letter}

% Minion Pro is used as the main font, if you don't
% have it installed uncomment this line or choose another pretty font
\setmainfont[Numbers=OldStyle]{Minion Pro}

% senders personal data
\def \first {Isac}
\def \last {Asimov}
\def \street {Random St. 21}
\def \city {9873 New York}

% recipient
\def \recipientHighlight {Human Resources}
\def \recipientRest {Some Company Ltd. \\ Some Street 123 \\ 12345 Some City}

% just for the blindtext
\usepackage{lipsum} 

\usepackage{polyglossia}
\setmainlanguage{english}

\begin{document}

% to show the folding marks
\foldingmarks

\letterstart

\salutation{Dear Sir or Madam,}

\lipsum[1-2]

\closing{Sincerely yours,}
\enclosure[Attached]{curriculum vit\ae{}}

\letterend

\end{document}