I've been playing guitar for about four years.

i'm decent, but i'm definantly not as good as someone who has taken lessons for four years.

i refuse to take them, but id like to improve greatly.

give me the best site/way to learn?

minus lessons/book.

i'll sit in front of this computer all day and play if thats what it takes.
...why? what possible reason could you have for not wanting to take the most sensible path to improvement, fair enough if all the teachers are awful or there aren't any. but actually just refuse is bat**** retarded.
yeah why not take lessons?
What you want to be know as that guy thats really awesome at guitar and its more impressive that his self taught? its not gonna work
some of the most worshipped guitar players took lessons its only common sense if you want to get better. good luck
Without knowing what it is you want to improve I'd say that'll be your first step. Pick a clear goal. Do you want to shred? Learn more theory? Play that song you like? Chicken pick? Get a better legato? Get a great vibrato? etc. Find something specific you want to improve.

From there you can find resources (books, DVDs, UG articles/lessons etc.) related to what you want to learn and hopefully be able to start constructing a structured approach to achieving your goal.

I'd highly recommend at least getting a book or DVD to give you a basis to work from as they're usually written/created with a specific goal in mind anyway and are likely to steer you in the right direction. This is also why teachers, good ones, are worth it. They help you identify your goals, and then provide a structured lesson and practice approach to help you reach them.

Good luck!