Page Columns (rather than table columns)

Hi all, just two quick questions:
1) if I set up a page with three columns and put a number of blocks in it -
a mixture of text and tables, how do specify that I want a table to span
multiple columns? note I am not talking about spanning cells here - I have a
table that is bigger than the width of the page columns so I want to flow
into across two page columns.
2) if I have a block which contains one line of text on its own how do I
stop this - I can see how to do it for a page but how for a column? i.e. the
line is on the 2nd column at the bottom and I would have preferred it to be
on the 3rd column at the top.
 
thanks in advance!
 
Philip.