Okay, I have at the moment:

PHP Code:

RewriteEngine on
RewriteRule ^([^/]*)\.html$ $1.php 


Which converts something.html to something.php. However, I want to make it go something.html to parse.php?action=something. I tried:

PHP Code:

RewriteEngine on
Rewrite Rule ^([^/]*)\.html$ parse.php?action=$1 


But that doesn't work. I get 404 error saying that something.html can't be found. I have never used mod rewrite before and don't really get these expressions so if someone could help me out I would be very grateful. =)

You can try this:

Single URL:

Options +FollowSymLinks
RewriteEngine on

RewriteRule parse-action-(.*)\.html parse.php?action=$1

Example: http://domain.com/parse-action-something.html


Directory Separated URL:

Options +FollowSymLinks
RewriteEngine on

RewriteRule parse/action/(.*) parse.php?action=$1

Example: http://domain.com/parse/action/something/

or
Comma separated:

Options +FollowSymLinks
RewriteEngine on

RewriteRule parse,(.*)\.html parse.php?action=$1

Example: http://domain.com/parse,something.html

Good luck!

Your regexp is correct. Did you really wrote "Rewrite Rule" in your .htaccess? Also try adding [L] after the rewrite expression so that this rewrite worked only once.

RewriteRule source destination [L]