The intermediate method is basically identical to the beginner method; there are just a few extra algorithms for directly solving some of the cube states that in the beginner method require the application of two or three algorithms.
The intermediate method adds two more algorithms for solving the whole LL from the one state that we can't make the yellow cross from in one algorithm:
TODO: ..but of course, there are 7 such states, not 2. Need to rethink this.
If you see this..  ..do this: 

F (R U R' U') S (R U R' U') Fw' The "S" move turns the middle slice between F and B, in the same direction as F. The "Xw" moves move two slices instead of the outermost slice. In other words, where F moves just the F slice, Fw moves the F and the middle slice, while leaving B in place. 

(R U) B' (Lw U [Lw' R'] U') (R' F R F') 
The above two algorithms are from Bob Burton's cubing site, as are the other OLL algorithms in the advanced and expert method.
In addition to the two algorithms from the beginner method, here are another two algorithms that can be used to directly solve the edges when they're swapped diagonally or directly opposite:
M2 U M2 U 

M2 U 
Done with the intermediate method? Proceed to the advanced method to learn how to solve the first two layers (F2L) at the same time.