\documentclass[a4paper,12pt]{article}
\usepackage[cp1251]{inputenc}
\usepackage[russian]{babel}
\frenchspacing
\makeatletter
\def\@makefnmark{\hbox{\@textsuperscript{\footnotesize\@thefnmark}}}
\makeatother
\begin{document}
Текст\footnote{Сноска}
\end{document}
% vim: fenc=cp1251:ts=4