Phlebotomy is the act or practice of opening a vein by incision or puncture to remove blood. Phlebotomists typically work in hospitals, doctor offices, or labs and take blood samples from patients for analysis.
Blood Collection: Routine Venipuncture and Specimen Handling
This tutorial, from the University of Utah Health Sciences Library, shows the step-by-step process of collecting blood samples. The site also has a chart for quickly identifying blood sample tube types.
Here are some websites where you can find reliable information about phlebotomy.