[eluser]Stefano G[/eluser]
The best place where you can learn about .htaccess is the apache documentation homepage but if you google "apache .htaccess" you will be displayed of thousands of pages!
Anyway I still don't understand why you are getting a 404, even because I usually work with the same configuration as yours (thus the one I explained before) and I don't have such problems!
Cheers
Stefano