When are puppies old enough to start eating, interacting w/ humans etc.?

[maytrix_free]

Well I guess that was self-explanatory enough.....this litter of pups have begun to open there eyes and either theyre trying to venture a few steps away from theyre little room or theyre still hanging on to the nipple when the mama gets up...in any case can someone give a brief, bottom line response to puppy development ages and stages? Thank you