Weblets UPN and the WB Network have unveiled long-term affiliation agreements with key station affils.

UPN’s expansion of its affiliate base comes as the weblet grapples with an uncertain future in light of the planned merger of one of its parent companies, Viacom, with CBS. That deal could force Viacom to divest its 50% interest in UPN — co-owned by Chris-Craft/United TV — to comply with federal regulations regarding network and station ownership.

The WB, meanwhile, has sealed a five-year renewal of its affiliation with Tribune Broadcasting, which owns a 25% stake in the weblet. Eleven of Tribune’s 18 major-market stations are WB affils.

Pact also calls for Tribune to shoulder a larger share of the WB’s startup losses. Details on that element of the deal were not disclosed and WB and Tribune execs were not available for comment late Friday. WB chief Jamie Kellner said in a statement that the weblet was on track to hit the break-even point during the 2000-01 season.

Meanwhile, UPN has added or renewed affiliation agreements with stations in eight markets, according to Steve Carlston, exec VP of affiliate relations. Most importantly, UPN will gain an affil in the San Diego market with the planned Oct. 1 sign-on of startup station XUPN, owned by Spanish-lingo broadcaster Entravision.

The weblet that serves up “Dilbert” and “Moesha” will soon be playing in Peoria, Ill., too, thanks to its new pact with WAOE-TV in the nation’s 110th-largest TV market. The remaining new or upgraded UPN affiliation deals involve stations in Greenville, S.C.; Madison, Wis.; Columbus, Ga.; Harlingen, Texas; and Lexington, Ky.