Can I add existing photos in my camera roll to a new photo stream? I just got a new MacBook Pro with the current version of iPhoto, which supports Photo Stream. I have an iPhone 4, but never had Photo Stream enabled because my previous computer couldn't run the version of iPhoto that was required to use it.

Anyway, I just enabled Photo Stream now, but it seems that it only includes photos that were taken after I enabled it. I have 350+ photos in my camera roll that I'd like to also include in Photo Stream. Is there any way I can import them or something?
You can only manually add photos to photostream from iPhoto or Aperture not from the iOS device currently,

So you'd need to sync with iPhoto and manually add to photostream through that.