The code looks fine, as far as it goes.
How did you test this?
What were the results?
How did those results differ from what you expected?
If you got a server error, what was in your server error log file?
If you type "http://www.example.com/load/index/1" into your browser, you should see the page produced by your script located at filepath /load/index.php when passed a query string of "id=1".
As far as "changing the URLs that appear as link on your pages and in the browser address bar," that is not what mod_rewrite does. To change those URLs, you must edit your HTML or modify your script(s) and/or database(s) to publish the new 'friendly' URLs. The code above will then tell the server how to convert requests for those friendly URLs, when they arrive at your server, back into a properly-formatted call to your script(s).
[added] Basically, it may be that your understanding of what mod_rewrite does is incomplete, and that you have completed only one of two required steps -- or one of three recommended steps. See the thread
Changing Dynamic URLs to Static URLs [webmasterworld.com] in our
Apache Forum Library [webmasterworld.com] for more information. [/added]
Jim