You can go with the Kenko Extension Tubes and use your kit lens, but you will need to get really close (like inches) from your subject to focus.
Or you can go with a true 1:1 macro like the Canon 100mm or Sigma 105mm, which will give you a working distance of about 12". The longer the focal legnth the farther away from the subject you can be and still get 1:1.
If your going to dive deep into macro then you definitly want a 1:1 macro. There is always the 60mm models but then you will have to get about 8" away from the subjects, which doesnt work well with alot of insects. So I would suggest the 100mm Canon or the 105mm Sigma. Both are superb lenses and I honestly cant find a true winner with either of these. They also work as normal lenses fixed at 100mm. You can pick them up used for about $425-$450, or new for around $500.
You will need a flash and flash bracket to get the flash near the front of the lens, and the Canon Off-shoe cable #2 ($50). Shoot the bugs at f/11 or 13, 1/200 or 1/250 sec. shutter, manual focus, for great results.
Hope this helps.