$0.02:
Palin is a BIG proponent of abstinence-only sexual education (which doesn't actually educate children about sex, and has been proven to be counterproductive at preventing teen pregnancy and STIs). She is also very pro-life/anti-abortion. Presumably she taught these same values to her children.
I see the choice of Palin for a VP as being tactical for a lot of reasons. One of the big ones is because she's a social conservative who espouses "traditional" values (gays bad, abstinence, no abortion). I see her as being picked to stand as a living example of someone who is firmly behind the social conservative movement. She has a son getting shipped off to Iraq. She has a 17 y/o daughter who is pregnant and keeping the child. These were both known before she was chosen as a VP.
I have a problem that the Reps are apparently using Palin's children as political fodder. As I understand, it was the Reps who launched the news about the daughter being pregnant (since it wasn't widely known outside of the Palins' circle). I think it is inconsiderate to use a pregnant young lady, going through something difficult, to advance a political agenda.
I do have a problem with Abstinence-Only sex-ed. It doesn't work. People still have sex, but they're taught that it's bad and they need to hide it. When you raise your kids like that, you end up with 17 y/o daughters who get pregnant and undercut many of their opportunities for the future. She's also getting pushed into a marriage that I predict is off to a bad start. They're not getting married because they want to commit to each other. They're getting married because they're supposed to commit to raising a kid.
If you actually want to cut down on the numbers of abortions, teach kids about their contraceptive options, make it clear how to take advantage of those options, and teach them to not be embarrassed for doing so.
I think it's a safe bet that her sexually active daughter was not on the pill. I think it's a safe bet that she wouldn't have let her daughter be.
It's not hypocritical, but it does illustrate a failed policy.