for the fleas you can get flea bombs from the supermarket. make sure you have a day outing planned! but they do work.

as for ants. hmm they are trickier. we used to get this honey concotion that was in very small tubs and the ants would be attracted to the sweetness and carry it back to the nest and feed the queen...soon meaning no more ants. but for the life of me i cant remember what they are called! arrghh! hopefully another BBer has a better memory...