Directing actors is a technical part of film making. It's not easy, and if your actors don't give good performances, chances are you won't have a good film. People can usually forgive bland cinematography and clunky editing – but if they don't believe the characters then you're going to have no chance in engaging the audience.
I go to a film school myself and so I haven't really done a lot of research online. I suspect that you wouldn't be able to find everything you need to know just by looking online.
If you're serious about filmmaking then I'd suggest you take some courses. If you just want to take it up as a hobby then the best way to learn is to practice.
Buy a camera (a good DSLR if you can afford it), get editing software on your computer (would recommend Final Cut Pro 7 if you own a Mac or Adobe Premiere Pro if you've got a PC) and shoot outdoors in natural lighting (cheaper and looks better if you can't light well).
Also, best way to study films is to watch films. Watch a lot of different kinds of cinema. If you like a certain director try and watch all their films, especially their early shorts if they have any.
Just did a quick google search and found a couple of sites:
for cinematography: http://filmmakeriq.com/2008/07/345-cinematography-techniques/
filmmaking in general: http://digital-filmmaking.blogspot.com/
Not sure if they're any good though, sorry mate.
If you're keen on getting a DSLR, this stackexchange site is perfect for information. http://photo.stackexchange.com/