1) she wants to be VP because she wants to sabotage the obama campaign.
2) she'll say all the right things, but she secretly wants him to lose to mccain.
3) because if mccain wins, she thinks she has an excellent shot in 2012.
4) if obama wins, it has the potential to become a two-term presidency, and she will become irrelevant. plus, bill might divorce her, thus ending their political/business arrangement.