once helena (or was it tannis? damn girls) told you to visit the crazy earl, go the rust commons west and enter crazy earls scrapyard, its located near to the Outeryard new-u-station. then go to the crazy earl, he ll give you 2 quests which can be done in the scrapyard (1. killing some spiderants/bandits and 2. picking up a bundle of tnt and blowing some stuff up). after finishing them, return to the earl. he ll give you to new missions, first collecting some skap flesh cans in kroms canyon (best combined with the reaper quest from the new haven bount board) and the krom killing quest itself.
More Info on Krom: http://borderlands.wikia.com/wiki/Krom