You can definitely buy DE on the internet, but usually the shipping is more expensive then the product. I bought mine at a local vender in town then only sell environmentally friendly cleaning and household goods. Do a goggle search in your area to find it. I bought a pound of it for $8 including taxes.
DE tastes like a combination between bentinite clay and flour, but be careful not to breath the dust in too much, could irritate your lungs. USE ONLY FOOD GRADE!!!
What else...has a drying effect on the body so you many need to drink extra water. When I first started taking it I noticed it constipated me, after the initially first 2 days taking it I did a flush to get my system moving again.
This is a good site for explaining the effects of DE.