You can use the enumitem package to redefine the environment:
\documentclass[a4paper]{article}
\usepackage{enumitem}
\makeatletter
\renewenvironment{thebibliography}[1]
{\section*{\refname}%
\@mkboth{\MakeUppercase\refname}{\MakeUppercase\refname}%
\begin{enumerate}[label={[\arabic{enumi}]},itemindent=*,leftmargin=4em]
\@openbib@code
\sloppy
\clubpenalty4000
\@clubpenalty \clubpenalty
\widowpenalty4000
\sfcode`\.\@m}
{\def\@noitemerr
{\@latex@warning{Empty `thebibliography' environment}}%
\end{enumerate}}
\makeatother
\begin{document}
\begin{thebibliography}{99}
\bibitem{Lorem}\textsc{Lorem ipsum dolor sit} \texttt{Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras
vitae purus mi. Fusce quam urna, elementum at ullamcorper in, tempus sed quam.}
\bibitem{Lorem2}\textsc{Lorem ipsum dolor sit} \texttt{Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras
vitae purus mi. Fusce quam urna, elementum at ullamcorper in, tempus sed quam.}
\end{thebibliography}
\end{document}
Adjust the value for leftmargin to suit you. Notice that the argument to thebibliography is still necessary, even if it does nothing. This way you won't need to modify the input if you change your mind.

Caveat
This code is meant for the standard class article. For report or book change \section into \chapter, while for KoMa-script classes or memoir some different hack might be necessary.
{99}in the beginning, instead of{9}. The number of 9's ought to correspond to the number of digits of the largest bib label. – yo' Apr 09 '12 at 17:06enumitem. What operating system and TeX distribution are you using? – egreg Apr 09 '12 at 17:42