I come to you as one reformed. I will no longer use foreach loops to build tables. At first, I did not know about theme_table. Then I couldn't be bothered to learn about it. Then, after feedback from people whose opinion I respect, I felt compelled to bite the bullet. I wish I hadn't waited so long.
Overview
As the name suggests, theme_table is a Drupal theming function for creating tables. It takes arrays holding the table data and generates the HTML for displaying the table. At their simplest, the input arrays hold text elements. At their most complex, the arrays hold arrays which hold arrays. The various arrays all hold data appropriate to their location, so this isn't as bad as it sounds.
As with all Drupal functions, there's documentation at api.drupal.org. For the Drupal 5 theme_table function specifically: api.drupal.org/api/5/function/theme_table. There's enough there to get you started, but you still have to think a bit. (Which is to say, I had to. Think a bit, that is.) Thinking should be reserved for the problem at hand, not figuring out Drupal, so here's my "overflowing with examples so you can cut and paste" explanation of theme_table.
