Phone polls vs. Internet polls

The T.V. likes to keep telling us that phone polls are "scientific", while internet polls are unscientific, indidcating they are skewed.

How can this be?

Phone polls are definitely skewed. First, this assumes the person has a land line. Second, it assumes these people they bug at home are likely voters.

Who is a more likely voter, someone you call randomly at home at night on their land line, or someone going to political websites and voluntarily filling out a poll?

I would say the internet user is more likely a voter.

Of course, both polls are skewed, but for us to give full credence to one and ignore the other is ridiculous!