I'm not finding programs via keyword "Cubs" via the Tivo and Comcast cable websites. So I'll have to find them elsewhere.

Today they had a program titled "Windy City Playoff Preview Special". I'm hoping they'll reair it.

Here is their schedule for the 2008 Postseason games.
Source: cubs.com
http://chicago.cubs.mlb.com/mlb/schedule/ps.jsp

Comcast Sportsnet Chicago is offering Cubs pre-game and post game programs. TBS is airing the actual playoff games.

So you might want to add this to your viewing/recording lineup:

Wednesday, October 1, 2008
Comcast Sportsnet Chicago
5:00p Cubs Pregame Live
5:30p Chicago Tribune Live (LIVE)
6:30p SportsNite (LIVE)

9:00p Cubs Postgame Live
10:00p SportsNite (LIVE)

TBS 5:30pm - 9pm Cubs vs Dodgers