The ordinary tabular environment cannot break across pages.  What you need to
do is include a line 
      
      \usepackage{supertab}

after your \documentclass line, and then use

	\begin{supertabular}{lp{4in}}
	whatever stuff & more stuff \nextline
	....
	\end{supertabular}

Note that \nextline should be used wherever you'd use \\ in the tabular
environment, except for the very last line.

Here's an example of a table done with the supertabular style:

	\tablehead{\hline
	Ster&Harvardnr&max&periode&\multicolumn{3}{l|}{Datum}\\
	\hline}
	\tabletail{\hline}

	\begin{supertabular}{|llrrrrc|}
	SS Cas &000451 &  8.8&140.57&30&jan&1989\nextline
	W Peg  &231425 &  7.9&344.92&27&apr&1989\nextline
	..... lots of extra data here ......
	S Peg  &231508 &  7.1&319.22& 4&dec&1989\nextline
	Z Peg  &235525 &  7.7&325.47&23&jun&1989\\
	\end{supertabular}

Note that you can create lines which will appear at the top and bottom of the
table on every page with the \tablehead and the \tabletail macros; if you
don't need to do this, you can just not use them.