There are going to be two special editions: The Premium Edition and the Ultimate Songbird Edition.
The Premium Edition includes:
-Murder of Crows vigor bottle keychain
- Resin cast Handyman figurine for the upcoming board game(?)
- Art book
- Several DLC items: Exclusive vigors, digital soundtrack, and platform exclusive content: Avatar outfits for Xbox Live and themes for the PS3 and computers. This all goes for about $80 USD.
Now, the Ultimate Songbird Edition includes all that plus...
A 9 and a half inch handpainted resin Songbird statue included in a special packaging within the box itself if you don't want to unwrap it at all. The statue was produced in limited quantities, so you'll have to preorder one soon if you really want it. The price for the Ultimate edition is a whopping $150 USD.
Official announcement here: http://irrationalgames.com/new-featured/premium-and-ultimate-songbird-edition-announced/
Preorder here: http://www.bioshockinfinite.com/collector/
PS: Personally, I'm just gonna get myself the Premium edition. I'm really not that crazy about the statue...