In a small bowl add sugar, lemon juice and some dish-washing liquid. I like to add some warm water so the sugar melts and the heats gives off a stronger more aromatic aroma to attract the little visitors. Place near the source of your fly problem and wait.
A few hours later your bowl will look something like this and your fly problem for the time being will be over.
Brilliant idea. Do you have a similar solution for cockroaches (the bane of Hawaiian life)?
mmm I have never had the privilege of living anywhere warm enough that would interest a cockroach but I did a quick search and found that my favorite insecticide Tea Tree Oil might be helpful for you.
http://www.ehow.com/facts_7520426_chemical-cure-getting-rid-cockroaches.html