Tables are, by default, set entirely in boxes of their own: as a result, they won't split over a page boundary. Sadly, the world keeps turning up tables longer than a single page that we need to typeset.
For simple tables (whose shape is highly regular), the simplest
solution may well be to use the tabbing environment,
which is tedious to set up, but which doesn't force the whole aligment
onto a single page.
The longtable package builds the whole table (in chunks), in
a first pass, and then uses information it has written to the .aux
file during later passes to get the setting "right" (the package
ordinarily manages to set tables in just two passes). Since the
package has overview of the whole table at the time it's doing
"final" setting, the table is set "uniformly" over its entire
length, with columns matching on consecutive pages.
longtable has a reputation for failing to interwork with
other packages, but it does work with colortbl, and its
author has provided the ltxtable package to provide (most
of) the facilities of tabularx (see
fixed-width tables) for long tables:
beware of its rather curious usage constraints - each long table
should be in a file of its own, and included by
\LTXtable{width}{file}. Since longtable's
multiple-page tables can't possibly live inside floats, the package
provides for captions within the longtable environment
itself.
The supertabular package starts and stops a
tabular environment for each page of the table. As a
result, each 'page worth' of the table is compiled independently, and
the widths of corresponding columns may differ on successive pages.
However, if the correspondence doesn't matter, or if your columns are
fixed-width, supertabular has the great advantage of doing
its job in a single run.
Both longtable and supertabular allow definition of head- and footlines for the table; longtable allows distinction of the first and last head and foot.
The xtab package fixes some infelicities of supertabular, and also provides a "last head" facility (though this, of course, destroys supertabular's advantage of operating in a single run).
The stabular package provides a simple-to-use "extension to
tabular" that allows it to typeset tables that run over
the end of a page; it also has usability extensions, but doesn't have
the head- and footline capabilities of the major packages.