Now let's see, where did I leave off..... PVP!
When it comes to ganking, with Rammus I prefer to gank the lane in which the enemy champs are at least halfway pushed out in their lane. Wards are no concern if you time your powerball right, being that you blaze right past them. If you know there aren't any wards, camping in grass alongside the lane is great too. Either way, you are going to be powerballing in about halfway through your duration with powerball, just to get your speed up, and going for the target who does not have flash, or the lowest in health if they both have a flash. With powerball and red buff, the double slow effect will actually mean that flash doesn't mean much, especially with a well timed taunt. Another important note that I forgot, Summoner skills! Of course, in jungle you have to take smite with rammus, and the 2nd choice is either ghost or flash. I choose flash every time because while normally ghost lets you ignore creep collision, this effect is negated when using powerball. Because surprise is of utter importance, and movement speed plus slowing your enemy is huge on a gank, it seems like a no brainer to me. One final point is that when people know rammus and see you plowing into a set of creeps, it is always funny to flash OVER the creeps and catch them unprepared.
This phase basically continues until the laning phase ends, with you occasionally covering solo lanes that need to recover. At this point... you wait until a little later for the End Game Phase and item builds! Today, I promise.