This plugin allows you to order posts by context (i.e. if you don't want to order posts by date).
Installing this plugin, as with any wordpress plugin, is relatively easy:
Open each of these files and find the line that reads:
Now, immediately before that line, paste the following code into archive.php:
And the following code into index.php:
To start using the installed plugin, simply login to your WordPress admin area, click on Manage and then Order Posts in the management sub-menu.
You will see a list of categories on your site and all the articles for each.
To start with, none of the posts within each category will be numbered correctly, but after the first time you move an article (either up or down) the plugin will give each article an order number (which displays on the very left of each article in the list.
Ordering is easy; simply click the [+] button for any article to move it down the list and [-] to move up the list.