Read his piece and understand why the more Obama and Biden bring this up, the more their hypocrisy (genuine hypocrisy, not the human frailty sort of thing that lefties like to call hypocrisy but isn't) is highlighted.
And a trenchant comment from Jonah Goldberg that is the exclamation point on this matter:
Now imagine if he was talking about food stamps or sex ed instead of the Bridge to Nowhere. You can be sure all the folks at the Obama campaign and TPM would be talking about how Sarah Palin killed the project dead.
* Following links from the site referenced above that wrote about the airbrushing of history, I found this link, where Governor Palin is explicitly credited with killing the bridge. I saved a copy of that last linked page to the hard drive, just in case!