in case people haven't figured out where to go for EV'ing in Johto, here's a few locations.
Well, you can also surf in Celadon city next to the game corner for Grimers, they have a 90% chance of showing up and give 1HP.
Krabby gives 1 attack and can be found in Cianwood, with a 67% chance with super rod and a 90% when you use rocksmash on a rock.
In Cianwood, Cherrygrove, and Olivine city, Tentacool can be found 90% of the time and gives 1 Special Defense EV.
Geodude can be found 60% of the time in Dark cave and outside the ruins of alph (with rock smash) 100% gives 1 defense EV.
Gastly gives 1 special attack EV and can be found in sprout tower, on the second floor 85% of the time.
1 speed EV can be obtained from Magikarp, which is found pretty much anywhere in water with an old rod.
If anyone has any better locations, feel free to post.