F2L (First Two Layers) Algorithms
I execute my F2L holding the cube with the cross on the left, and present my algorithms thus. Bottom-cross and left-cross F2L have their own advantages and disadvantages: bottom-cross gives better visibility and look-ahead, left-cross lends itself to slightly easier execution if you're right handed, with almost exclusively F, R and U moves.
My advice for beginners is to learn F2L by figuring out how it works intuitively, rather than rote memorization. These algorithms are provided as a reference, especially for less intuitive cases. Thus, even if you choose to solve cross on bottom, you should still be able to figure things out.