If you have the patience you can use the wet towel method.. soak a towel in fresh water and drape it over your bonnet/bumper.. leave for a while then come back and the bugs just wipe off with a sponge.
For my own cars, I don't even use a soap, just rainwater and a sponge. Wash once a week then wax, the paint stays so smoothe you don't need to scrub at the bugs and spots, they just wipe straight off. Takes a bit of groundwork to get your paint to that stage first though if you have an older car... a Meguiar's clay bar is a great place to start.
Sam