Fingertip pushups can be a neato thing to practice to some degree, but take care just as you would with your knees while running, to prevent injury. Personally I prefer to use free weights to strengthen the hands. Just as you can do wrist curls you can also do finger curls. After a while pushups on one finger without the balance of the thumb are possible.
"After all, we all have only two arms and two legs." "Death is certain, life is not."