What is the training program for the Navy SEALS called?

Members of the Navy who want to become Navy SEALS must first pass the PST (Physical Screening Test). This is a grueling physical test that all candidates must go through. Those who pass are entitled to enter the BUD/S (Basic Underwater Demolition) program.

Source:

UUS Navy SEAL Fitness Training

Seal Challenge: U.S. Navy SEAL Information