The Barack Obama campaign has found a fourth network to air its half-hour “campaign-related program” — MSNBC.

The Washington Post’s Lisa de Moraes reports the original plan was to air the ad at 8pm as a roadblock across the four broadcast networks, ABC, CBS, FOX and NBC. But ABC had an hour-long program slotted for 8pm, and “originally offered to sell Obama’s campaign other time slots on other nights.”

But by the time ABC “decided to slide their entire prime-time lineup,” the Obama campaign had already chosen MSNBC as the fourth network.

So tomorrow night, it’s the Obama “program” on the networks — or “Pushing Daisies” on ABC. de Moraes reports, “ABC already has begun airing ads telling viewers, ‘Wednesday you have a choice — get political with the other networks or’ watch a new episode of ‘Pushing Daisies.’”

And on MSNBC, the half-hour Obama ad will preempt the first half of Countdown with Keith Olbermann, with a half-hour Countdown beginning at 8:30pmET. An entire new hour of Countdown airs at 10pmET.

> Update: BET and Univision will also air, as its called on TVGuide.com, the “Barack Obama Political Message.”