navigate and paginate by month

Hi

Is there a way to modify the loop so that a page of posts is limited by the month that is being viewed, regardless of if you are viewing a category listing of posts or just the blog-roll?

I am transferring a static news site with several years of content into a cms so would like to try and maintain the same views as set in the current static site.

I tried to modify the loop with get_lastpostdate() but I cannot get the previous/next navigation to show anything else but the get_lastpostdate().

<?php	$lastpost = strtotime(get_lastpostdate());
		$lastmonth = date('m', $lastpost);
		$lastyear = date('Y', $lastpost);
		$args=array(
			  'post_type' => 'post',
			  'post_status' => 'publish',
			  'year'=>$lastyear,
			  'monthnum'=>$lastmonth,
			  'order'=>'DESC',
			  'posts_per_page' =>50
		);
		query_posts($args);
?>

The reason I used get_lastpostdate() is that there could be instances where there are no posts for a month. I thought that this would at least fix this issue for the initial view.

I’m a bit stuck on this so any advice on this would be greatly appreciated.

I do have additional questions, such as how to change the paged url navigation from %category%/page/2 to something like %category%/%month-year%. But I think the pagination is much more critical.

Are there any resources that I should read up on to try and understand this better?

Thanks