this is pretty easy to do. What you need is a custom home.php file. You can start by copying your index.php and renaming it home.php. Delete the sidebar reference and put the entire thing in a div tag with id=homepage and set up your css accordingly.
I recommend reading the codex on query posts to get a better understanding of what can and can't be done in regards to this function as that is how you will call your posts. There plenty of free examples of themes using this technique to look at.
Here is a quick example off the homepage of bradstinyworld.com
` <div class="hometitle">Pop Culture Pop Tarts</div>
<?php $recent = new WP_Query("cat=17&showposts=3"); while($recent->have_posts()) : $recent->the_post();?>
" rel="bookmark"><img style="padding:5px 0px 2px 0px;" src="<?php echo get_post_meta($post->ID, "thumbnail", true); ?>" alt="<?php echo get_post_meta($post->ID, "Theme Name", true); ?> Thumbnail" width=260 />
<h4>" rel="bookmark"><?php the_title(); ?></h4>
<?php the_content_limit(175, "[Read more]"); ?>
<?php endwhile; ?>
This calls on the posts from cat number 17 which in this case is pop culture. I tells it to display 3 posts and show the predefined thumbnail if there is one. you can do a lot with the query so I suggest reading up and playing around.