the stinky smell in the coming off the vents is usually caused by:
1. dirt deposits on the cabin microfilter : change it. takes 15-45 mins to replace depending on your mcgiver skills.
2. clogged drain. locate where the drain is under your car. try blowing compressed air into it.
3. condensation in your a/c evaporator (the alluminum fins inside the box under the dash where cold refrigerant passes). when the room temp gets hotter, the condensate becomes a breeding ground for bacteria and the bad smell. just like what happens to your damp socks sitting inside a plastic bag for days. the solution is to run your fan high, turn your heater up and recirculate the air for 15 mins with all doors and windows closed. this will dry up your evaporator. then practise the habit of turning off the A/C and leaving the fan on about 15 minutes before reaching your destination to prevent bacteria buildup. see www.airsept.com
for more info. they also have this antibacterial spray that you need get into where the cabin microfilter sits. this spray places a coating on the evaporator that prevents it from holding water.
bear, spraying lysol at the air intake does not do much since the spray will only be trapped by the intervening cabin filter in models where it is present. except, of course, if you meant that you need to remove the cabin filter first before spraying.