I use netafim you can get it at a irrigation supply house or here at sprinklerwarehouse.http://www.sprinklerwarehouse.com/Landscape-Dripline-0-9gph-12-inch-spacing-100ft-p/ld0912-100.htm
to measure how much you need of how much line you need is:
1. Multipy the square footage (LxW) of the area times 12
2. Divide that number by the minimum number of inches apart the rows should be.
So if you had a flowerbed 15ft by 12ft - 15x12=180sqft /180sqft times 12 = 2160sqft divided by 6 inch spacing = 360ft of tubing.
Do you have a flower bed you are converting, if so they have a easy conversion kits out there.
Jimmy
Texas Lic. Irrigator
Landscape Irrigation Auditing & Management
Texas Lic. Backflow Tester