My five year old has just started helping with the washing up, and she will sometimes unbidden put her toys away or attempt to sweep the floor or "clean" (smear and make worse, but I don't like to discourage her) the windows. I don't want to tie it to pocket money because I think that offering a reward reinforces the idea that this stuff is not something you want to do,whereas at the moment she is happy to do it and accepts that everyone who lives in our house needs to do their bit. We'll see what happens as she gets older.
My four year old does the occasional job like getting firewood or putting the cutlery away. The 8yr old has to unstack the dishwasher. The 16yr old does stuff that needs doing. She started really helping out at about 10 I think.
My four year old boy loves to help, though similar to Jennifer's daughter, that can be more of a hindrance in reality! But I think it's all part of developing a healthy attitude towards being helpful and pulling his weight around the house so I encourage him.
I don't like those lists that circulate saying "these are the chores your child SHOULD ne doing by this age" as partly I dislike anything so prescriptive and partly I think each child and family is different, so you should work with who you are and what your circumstances are. I think an ad hoc approach working with your child's enthusiasms is best.
As for rewarding with money, I would not and will not do that. Not for every day, mundane stuff around the house. Maybe if it's something out of the ordinary but the usual things that have to happen so the household functions, everyone needs to pull their weight and muck in to do those and the reward is that the house is clean, there is food to eat and clean clothes to wear. Just like for adults.
My kids love "helping", but so far it is very haphazard lol They just help when they feel like it. Ms 3 loves putting things in the washing machine, making mummy's coffee and helping cook. Mr 1 and a half likes to help sweep and put clothes away in drawers...which is why I can never find anyone's clothes!! I don't like the idea of tying normal household chores to pocket money - everyone has to do their bit to help out. I'd probably give pocket money for "out of the ordinary" things like washing the car, mowing the grass, washing windows etc