Tom Gorzelanny is a good risky pick if you are looking to hit it big ... he could be killer the rest of the year, or nosedive. Phil Humber's also a good waiver option right now, along with Carmona, Harang, and Correia.
Thinking about it carefully, I'd probably sort that group:
Tier A: Colon (huge k-rate, some solid starts, subject to a bad game here and there pitching in Yankee Stadium)
Tier B: Carmona (consistently good, getting lots of wins and QS, low k-rate ~5.5/9), Narveson (has pitched awesome minus 2 starts, solid k-rate)
Tier C: Pinerio (Has pitched awesome coming off the DL, but who knows if it can be sustained ... decent flyer though), Wolf (lots of good games, a few stinkers, solid depth guy), Harang (blistering start, started to slow down)
Tier D: Correia (a couple bad starts this year, but has pitched well)
Gamble: Tom Gorzelanny (could be a top guy, or a stinker being on the nationals)