Quitting a Job

Hey guys and girls

So I'm in a job for less than 3 months now, and although I tried everything to make it work, I just don't think I can anymore. I think the compatibility isn't there, for both sides. So I'm ready to quit.

I signed a standard employment contract in February stating the first 3 months is a probation period. It ends Monday. In my point of view, it stands for both parties. I haven't looked at it again to remember exactly what the terms were, it's at home and I'm not, now.

So I wanted to resign tomorrow or Friday. My question is: how do I do it?

Both legally and "morally" (will not use the term ethically, as I don't think it applies here), should I say I'm leaving effective today (I can, right?) being it's probation, or should I say I'm leaving in 2 weeks? I don't think I would be able to withstand another 2 weeks. And I also think if I say that, the company is going to say they don't need the 2 weeks (because it's still probation and also because they may as well feel how I'm feeling), and let me go immediately.

What do you guys think? Any opinion counts, shoot away please.

Thanks a bunch.
Your always Douche