You can also try the package TABLE from River Valley. The package provides the following:
- include a landscape table as a float.
- format the caption exactly to the width of the table.
- some other hooks that would add a little extra vertical space around horizontal rules in the tabular.
And it automatically centre the table on the page.
Here is a modified example from the readme-file
\documentclass[a4paper,landscape]{article}
\usepackage{txfonts,array}
\usepackage{Table}
\begin{document}
\TABLE{\label{tab407}Distribution of Turnover and Market
Capitalisation of Top `50' Companies listed at NSE}
{\tabcolsep8pt\extrarowheight2pt
\begin{tabular}{@{}lrrrrrrcrrrrrr@{}}
\br
& \multicolumn{13}{c}{Turnover}\\\ns
& \crule{13} \\
& \multicolumn{6}{c}{Amount (Rs. crore)} & &\multicolumn{6}{c}{\% to total}\\
& \crule{6} & & \crule{6}\\
Companies& 1995--96 & 1996--97 & 1997--98 & 1998--99 & 1999--00& 2000--01&&
1995--96 &1996--97 &1997--98 &1998--99 &1999--00 &2000--01 \\
\mr
Manufacturing &49,909 &131,109& 132,678 & 88,224 & 139,742& 124,779 && 79.29& 45.88 &37.43 & 23.13 & 18.78 & 9.85\\
Financial Services &10,859 &100,037& 54,071 & 26,500 & 34,308& 17,559 & & 17.25& 35.01 &15.25 & 6.95 & 4.61 & 1.39\\
F.M.C.G &704 &43,818 & 155,148 & 94,240 & 38,011& 32,438 & & 1.12 & 15.33 &43.77 & 24.71 & 5.11 & 2.56\\
I.T. &0 &159 & 2,579 & 138,148 & 369,315& 957,159& & 0.00 & 0.06 &0.73 & 36.22 & 49.63 & 75.56\\
Pharmaceuticals &158 &408 & 1,976 & 9,029 & 48,230& 21,085 & & 0.25 & 0.14 &0.56 & 2.37 & 6.48 & 1.66\\
Others &1,313 &10,229 & 8,048 & 25,285 & 114,481& 113,803 && 2.09 & 3.58 &2.27 & 6.63 & 15.39 & 8.98\\
\mr
Total &62,943 &285,762& 354,500& 381,427& 744,088 & 1,266,823 & & 100.00 & 100.00 & 100.00 & 100.00 & 100.00 & 100.00\\
\br
& \\
& \\
& \multicolumn{13}{c}{Market Capitalisation}\\
& \crule{13}\\
& \multicolumn{6}{c}{Amount (Rs. crore)} & & \multicolumn{6}{c}{\% to total}\\\ns
& \crule{6} & & \crule{6}\\
Companies & 1995--96 & 1996--97 & 1997--98 & 1998--99 & 1999--00 & 2000--01 & & 1995--96 & 1996--97 & 1997--98 & 1998--99 & 1999--00 & 2000--01\\
\br
Manufacturing &139,546&162,188&177,371& 106,572& 151,692 &96,718& & 62.05 &62.18 &54.95 &34.39 &20.53 &20.79\\
Financial Services &25,655 &29,083 &34,061 & 18,334& 36,209 &36,460& & 11.41 &11.15 &10.55 &5.92 &4.90 &7.84\\
F.M.C.G &22,648 &29,888 &59,199 & 90,773& 79,522 &80,497& & 10.07 &11.46 &18.34 &29.29 &10.76 &17.30\\
I.T. &0 &0 &8,434 & 45,742& 306,418 &106,095& & 0.00 &0.00 &2.61 &14.76 &41.48 &22.80\\
Pharmaceuticals &4,168 &4,728 &8,176 & 24,221& 19,324 &21,035& & 1.85 &1.81 &2.53 &7.82 &2.62 &4.52\\
Others &32,880 &34,934 &35,545 & 24,272& 145,609 &124,502& & 14.62 &13.39 &11.01 &7.83 &19.71 &26.76\\
Total &224,897&260,821&322,786& 309,912& 738,774 &465,306&& 100.00 & 100.00& 100.00 &100.00 &100.00 &100.00 \\
\br
\end{tabular}}
{\textsc{f.m.c.g.} Fast Moving Consumer Goods Market
Concentration in Emerging Asian Markets: end 2000 Market
Concentration in Emerging Asian Markets: end 2000\\
\textsc{i.t.} Information Technology}
\end{document}
Which gives the following output:

\begin{center} \end{center}don't work? – R. M. Sep 28 '12 at 14:23\centeringshould have the same effect right? If not, I could try. I solved the problem by adding thetableenvironment (see answer). – simon Sep 28 '12 at 14:28\centeringhas the same effect but it must be putted on an environment. If you don't want the a floating table (\begin{table}) you can use thecenterenvironment. – R. M. Sep 28 '12 at 15:48