TVGuide has posted a letter from Smallville creators' Alfred Gough & Miles Millar, stating that they have decided to step down from the series after 7 seasons.
You can read the full letter below:

An open letter from Alfred Gough and Miles Millar, creators and executive producers of Smallville.

As the creators of Smallville we look back at 7 amazing years. We look back at 152 episodes. We look back knowing that the show will continue into Season 8 without us. After much heartache and debate we have decided it is time for us to move on.

Over the last 7 years we have had the honor of working with a remarkable team of people here in Los Angeles and in Vancouver. We have been blessed with a wonderful cast who we have watched mature with admiration and affection. We have been rewarded with a fan base that is as loyal as it is vocal.

We are incredibly proud of our work on this show. We achieved what we set out to do. We never compromised our vision. We leave knowing that Smallville is the longest — running comic book based series of all — time. The show was featured on the covers of Rolling Stone, MAD magazine, TV Guide and Entertainment Weekly. The pilot had the highest — rated premiere in the history of the WB. Even in its seventh year it is still the #1 scripted show on the network. Smallville is watched by millions of people in hundreds of countries and in dozens of languages around the world.

The show's success is a credit to a fantastically talented group of people.
We wanted to take this chance to single some of them out:

Our writers — your work speaks for itself.
James, Jae, Rob, David — the backbone of our team in Vancouver.
Joe Davola, Chris and Shelly — remember those Friday night brainstorming sessions?
Len Goldstein and Steve Pearlman — thanks for believing we could do this. David Nutter — for giving the show your magic touch.
John Litvack — when the knives were out, you always had our backs.
Ken Horton — our Yoda.
Peter Roth — Smallville's biggest fan.
Melinda, Michael R., Paul M., Susan and Suzanne — for steering us through 152 episodes.
Greg Beeman — your passion is an inspiration.
Jordan, David, Garth, Carolyn, Bob & Lew — and everyone at the much — missed WB.
Paul Levitz, Greg Noveck and the guys at DC Comics.
Lisa Lewis — our very own soccer mom/mafia accountant.
Michael Gendler — aka mega — counsel.
David Lubliner — we can finally focus on features now.
And last but in no way the least, Renee Kurtz — the smartest TV agent in town, we would be nowhere without you!

Finally, to the fans who have stuck with us through the highs and the lows:
know this — we never stopped fighting to make this show great. Thanks for watching.

Alfred Gough & Miles Millar

Labels: News, Smallville