If you notice large amounts of bees, one of the easiest methods is to contact a local beekeeper to locate and remove the hive. Climate changes have led to drastic reductions of the bee population and they will often remove the bees from your area for free. Simply do an Internet search and call them.
If you have only a few bees in your yard, you can create a simple bee trap by recycling a plastic soda bottle -- bees and wasps will be attracted to the trap but they will be unable to escape. Cut off the soda bottle top where it starts to curve. Flip it upside down and insert it like a funnel into the bottom. Duct tape the parts together and pour in the soda or juice.
Another simple way to reduce the number of bees in your garden or yard is to use boric acid, or borax powder. Sprinkle the borax on plants you see frequented by bees. The powder will stick to their hairy legs and it will be carried back to the hive, effectively killing the hive within days. Boric acid is a known insecticide used in the removal of other pests, such as roaches. It dries out the exoskeleton and kills the pest. Because it is slow acting, the bees have time to carry it back to the nest where they spread the poison. This method is beneficial because boric acid/borax poses almost no risk to humans.