u ve already got some really helpful replies... but i wud like to stress on the fact that u need to make absolutely SURE that the mileage is not tempered... there is no way to be sure but look for clues, is the steering wheel worn out a bit? if the steering wheel is shiny at the outer turning circle or if the surface is very smooth, the car probably has three times the mileage stated by the owner 
then look for any worn out paint on the central console, just above the a/c button and the areas around the cassette player housing.
look for faded paint in the door sills, see if the silver paint of the gear shifter knob is faded etc etc.... pick up small clues for every single panel and then turn these into a conclusion. although all of this might be there even if the car has relatively low milage (due to irresponsible and careless owner) but still, u shud be able to distinguish... after all, its a subjective approach...
there is another way that i use to check the mileage of cars.though it doesnt work always. i hardly ever let the owner know what and why am i doing but if i do, they are absolutely stunned by this approach 
here it is...
the tires of a car have their manufacturing year and week mentioned on them. for a car driven just 52,000kms, it should have either its stock tires that came from the factory or replaced just once.... if the tires are worn out, check the dates on the tires, if they tell u the tires are older then the car itself (if its still on stock tires) the mileage can be assumed to be true. if the tires have a recent date (1 or 2 years old.i.e. much newer then the car) and still they are worn out, u ve got a mileage tempering case here
u can also estimate the avg kms driven on the car in a particular period by looking at the tires' age. if the meter shows 52000kms, tires show a recent date but they are still half way through their life, this means the car travels a lot and mileage is probably tempered...
anyways, all of these are just estimates and they can vary a lot by changing the factors, this tire date approach seems to be the last resort for a car that is very well kept where other parts would not speak up the mileage of the car...
