<p>I have a page that spits out db data in long horizontal tables. </p>

<p>I need to print it nicely so it does not cut off. Any tips ?</p>

If it doesn't fit on the paper in a readable font, it just doesn't.. In my opinion, huge horizontal tables (be it a HTML table or an Excel sheet with many columns) don't lend well to printing. For that matter, they don't lend well to viewing on a screen either. Remember vertical scrolling is much easier for your users than horizontal scrolling - all thanks to that little wheel on your mouse.
Worst case, you might need to write a seperate print version which uses a vertical layout.