Variety is reporting that the WB Network has picked up the option for another season of Smallville.  The youthful saga of Superman's formative years is just about to end its third season on the Frog.  Although both Smallville and Everwood, which the WB also renewed, have dropped in the Neilson ratings this year, Smallville remains the WB's top-rated series with the coveted 12-34 demographic.  Equally important was the premium price of $750,000 per episode, which Smallville recently earned in a less than robust syndication market (see 'ABC Family Nabs Smallville Reruns').  In addition to Smallville and Everwood, the Frog has also renewed Seventh Heaven, Charmed, and the Gilmore Girls.  WB Network chairman Jordan Levin referred to the five series as 'the cornerstones of our schedule.'