Bioware's Signature Edition upgrade offer ended on 1/11. But, if you preorder now, you'll still be getting some goodies. Bioware released a news post on 1/13 which details three pieces of bonus content for post 1/11 pre-orders.
The Lion of Orlais
This is a shield that would be good for a PC tank. Along with a fearsome and rather un-Orlesian look, this shield gives a bonus to health and XP gain. (This may be related to Richard, Coeur de Lion, but that's for another post)
Fadeshear is an "heirloom" style sword whose stats will increase as you level up. The sword's bonuses are increased damage against Undead and Demon mobs. With no universal stat bonuses, however, this may be a situational weapon.
The Black Emporium
A mysterious shop nestled deep under Kirkwall, this is likely to be a "free with new purchase" DLC item, similar to DA:O's "The Stone Prisoner" and ME2's Cerberus Network. The store features some unique items both for sale and for free, and may be where you can acquire the Lion of Orlais and the Fadeshear, along with some for-now unnamed goodies and three additional features, including these:
- Hawke's own Mabari. The Black Emporium will sell a whistle to summon your own Mabari companion. This seems like more a summon than a party member, and therefore Dog's plateau of usefulness in Origins will be less of an issue. And who doesn't want a Mabari?
- The Mirror of Transformation. This will give you the chance to change your character's look if you're not happy with the epicness of Hawke's default beard.
- Rune and crafting shop. This will give you unique runes and items that would otherwise be unavailable in the game's other shops.
So, to wrap up, If you got your pre-ordered before 1/11, you got all these goodies in addition to a free download of an additional companion, Sebastian Vael, and his mission, the armory with four promotional weapons, and a downloadable game soundtrack. Any subsequent pre-order will give you these two weapons and the Emporium download. New purchases will get the Emporium download. If you missed the Signature Edition date, or if you buy pre-owned, you will likely be able to download the Black Emporium and Sebastian Vael, the Rogue with the Brogue, for an additional fee.