Someone I read—can't remember who—predicted that this election will spell the end of the cellphoneless poll. I dunno about the end, but this—from a good polling analysis/roundup by Mark Blumenthal—is worth keeping in mind:
At the national level, however, many national surveys are now using dual samples to reach voters on both landline and cell phones. It is probably not a coincidence that three of the biggest Republican leads on the national "generic" House vote were produced by pollsters (Rasmussen Reports, CNN/ORC and Fox/Opinion Dynamics) that are not calling cell phones.
It's worth noting here that Rasmussen and Fox polls have been favoring Mark Kirk. PPP's most recent poll did as well, and I don't think they poll cell-phone users. If Giannoulias bucks those polls, it's worth considering cell phones as a factor.