American viewers can access the replay of Heroes TV Episode 15 - "Run!" through the NBC TV website.
(links open in new window)

Heroes - Episode 15 - "Run!"

International viewers who would like to see the 15th Episode of Heroes, called "RUN!" can access Episode #15 through the TV Links (UK) site:

Heroes - Episode 15 - "Run!" (via TV Links site and Ouou)

Enjoy!