Miscellany

\documentclass[12pt,a4paper]{article}

\usepackage[english,greek]{babel}
\usepackage{ucs}
\usepackage[utf8x]{inputenc}

\begin{document}
\selectlanguage{english}
bla bla bla
\selectlanguage{greek}
βλα βλα βλα
\end{document}