Steve, you really don't need to bother with a fancy bomb even if there is such a thing.
Know thine enemy, learn the flea life cycle.
Flea eggs and larva live in the fibres of your carpets and in gaps of furniture and they thrive because they are the places you miss when hoovering - a popular place is the edge of the floor where the carpet joins the skirting board. But also remember... just because you hoover the ruddy things up, doesn't mean they are dead. They can still mature in the dustbag.
I spray the corners and edges of my floors, under sofas and cracks of furniture with Indorex once every six months. Change your dustbag regularly, treat your cats with a GOOD quality treatment and you won't have fleas.