Go to the wiki (there's a link on the forum's bar above). Look up stuff till you puke. Make a decision on how dedicated you want to get. Here's a brief overview of methods:
Fridrich: the most popular method. Literally hundreds, if not thousands, of sites out there to help you. The best part about Fridrich: you don't have to drastically change your method and you can modify it very easily (ZZ, VH, ZB, WV, etc. I use VH). Lots of algs? Sure, but they're really easy once you get used to the idea of new algs.
Petrus: a great way to learn how the cube works. Lots of intuition on the first 2 steps. However, the last layer is a bit meh and many use OLL+PLL for the Petrus LL. However, the edge orientation works out very well for last layer methods such as Winter's Variation and ZBLL. Also, it cuts down on the algs you need to learn, at the cost of thinking more during the solve.
Roux: a hybrid CF method. The first 2 steps require a lot of thinking (similar to F2L thought-process from Fridrich). The last step (4) is so much fun once you get good at M slices. It even requires some thought. Roux is hard to modify because it is already a hybrid method.
Corners First: I'm going to write more here because there is so little info on this method group. CF is very general method (Waterman, Ortega are the best known), but the idea is the same (for the most part): solve the corners, solve one face, solve the opposite face, orient the midges, and permute. This is the section of cubing that really has yet to be explored. It used to be (read: 20 years ago) all the rage, but it has died down mostly due to the rise of Fridrich. Corners First is a method with weird fingertricks that take some getting used to. There are variants where you can solve one face before the opposite corners. Some variants require tons of algs, others very few. But once you solve all the corners and the L face, the cube can be solved with the <R,U,M> generator group, which is very fast. However, since so little is known about CF, few people go for this route.
There are other methods, but these are the big 4. Take your pick and keep cubing!
