Sorry, I misunderstood your original question (I didn't read carefully enough). As others said, the next step for you is to contact your friend's doctor and let the doctor know you're interested in being considered for donation. If you friend is eligible for a transplant, you can be tested for compatibility.
Information on testing, surgery, and after care can be found on the LDO web site, along with donor buddies and stories shared by living donors about their experiences.
Hope this helps!