Thank you Basically they are just metal tubes that have threads on them to attach to your lens and camera. You place them between the lens and camera, therefore increasing the distance between the glass and the sensor - this allows for longer/closer focussing.
You can attach them to a regular lens to create a macro effect.
You can get very cheap tubes that are just the tube, or you can get some more expensive brand name ones that have glass in them.
The set I bought was only about 20 bucks from ebay and they seem to work very effectively - it's just a matter of getting used to them!
I have no doubt that you will do wonderful, you have such a beautiful eye for pics like this. And practice is fun! I am still getting the hang of my macro lens but I am having a blast as I feel everything out.
After seeing your work and that of a few others I think I am going to have to jump on the water drop bandwagon. I am getting much too envious