The plumbing aspect of this shouldn't be significant, though you won't get a dishwasher to fit under a sink. A source of water above an electrical appliance woudn't be the best of ideas anyway.
Plumbing component is just a matter of taking an extra feed off the cold supply, and plumbing the outlet into the waste. Do you have a 600 mil cabinet you could remove without damaging the adjoining units?
Depending on the layout of the kitchen and the location of the dishwasher relative to the washing machine, it may be an akward job.
You will also need a socket near the dishwasher location, if one isn't availailable, you'll probably have to call in an electrician to add one.
Afraid I can't help with estimates of cost.
Leo