Flea collars!
Now, I'm not a moron...
For people who have vaccum cleaners with a bag, change the bag after vaccuming once you start to "treat" the house for fleas. Clipa section of a flea collar off and put it in the new bag. It'll help kill remaining fleas in the tubes, and any that will enter the bag later on. Vaccum bags can be a breeding ground for fleas.
For those who have canister vaccums (bagless) the same can apply by putting a bit in the canister section.
In all instances, be aware of child safety practices though.