custom order of posts based on category and custom field on the index page

Hello,

I am modifying the “WordPress Default 1.6” theme’s index page and trying to re-organize how posts are showing up. The site is for a realtor and he wants to the posts to not sort by date posted but also by category and by a custom field that is assigned too.

<?php if (have_posts()) : ?>

<?php while (have_posts()) : the_post(); ?>

That is the beginning of the loop that will display the posts, are there any parameters that I can pass to those functions so that I can customize how the posts are displayed?

Thanks,