Prah’s gotten a head start on shilling for her new network.

OWN (Oprah Winfrey Network) won’t launch until January 2011, but Winfrey is already plumping for her startup channel, which will replace Discovery Health.

And she’s using her Web site, which will become part of that new network, to spread the word — a week after announcing the end of “Oprah” in Sept. 2011.

“Fifteen years ago, I wrote in my journal that one day I would create a television network, as I always felt my show was just the beginning of what the future could hold,” Winfrey writes in an oprah.com newsletter, e-mailed to subscribers.

The e-mail includes a promotional video for OWN.