remove colon from table name

I suggest you load the package caption with the following option:

\usepackage{caption}
\captionsetup[table]{labelsep=space}

If you want this setting, i.e., a space instead of a colon, to apply to figure environments as well, you'd just remove the [table] option from the \captionsetup command.

A separate issue: To get the caption to print above the body of the float, all you need to do is to specify the caption (and its label, if any) after the \begin{table/figure} command but before starting a tabular environment and/or before including some external graphics file.

Use the caption package with the labelsep=space option to achieve this.

Here's an example:

\documentclass{article}

\usepackage[labelsep=space]{caption}

\begin{document}

\begin{table}
\caption{An example of a table}
\begin{tabular}{ l c r }
  1 & 2 & 3 \\
  4 & 5 & 6 \\
  7 & 8 & 9 \\
\end{tabular}
\end{table}

\end{document}