Evolution sim Spore is to get its first expansion pack this spring.
That's according to an invite sent out to US websites such as Kotaku. It states that an event is being held in San Francisco to reveal the "Spore line-up for 2009", including "our first expansion pack, Spore Galactic Adventures".
The invite also reveals the add-on will be "available this spring". Seeing as the main game was released within the same week in the US and Europe, it's reasonable to assume the expansion will arrive around the same time too.