My Whirlpool Estate washing machine will not spin during the spin cycle?

My washing machine has had trouble spinning during the spin cycle for a little while now. Before, I could get it started and it would spin fine but now it won't really spin at all and eventually slows to a stop once I get it going. Is this something I should be able to fix on my own? (I am moderately skilled and able to follow directions pretty well) Do I need to have someone look at it? Or, would it be better to just get a new one?