How long does it take the ipod touch to charge?

I don't know really because people say about 3 hours but when I plug it into my wii about 30 minutes later it's halfway charged 0_0. I have a 2g iPod and I'm answering the question from it :p

i have a iPod touch and it was low i let it charge and it took 15 minutes to go to about halfway and I'm looking at it right now i have 8g

i have a 4th gen and when i plug it in the wall charger it takes like 30 mins to charge