its only when you walk i think. No they dosnt level up when the game is off it dosent work like that.
*whew* I only had my DS for a short ammount of time. I can't play it again until I'm done w/ algebra. (which will hopefully be this week) I saved and turned it off when Zoroark and Ditto were still in the day care. I plan to 1st obtain all the starters with baby Zorua's. Then, Resiram. And after that, just any rare-ish poke I want. I've seen people asking for ridiculous things for Zorua on the GTS. They must think it's like Munchlax or something.
I had 2 Eevee in the daycare in Pearl, but i chained so much thar they must have gone to Lv 100, i dont know because I abandoned them when i deleted the game file
Haha on Emerald one time, I put an Oddish in the day care and left it in there for a looong time. I got it out and it was level 98. I had to pay a lot.