The game only launched today, but Angry Birds Space rocketed past Draw Something as the #1 top selling and top grossing app for the iOS platform, and it continues to climb into an orbit all its own on the iTunes App Store. (OK, enough space cliches).
Zynga just recently purchased Draw Something developer OMGPOP just in time to see the app lose its foothold on the top spot.
Angry Birds developer Rovio has built a strong name for the franchise and I suspect that Rovio and Zynga will be going head-to-head a bit more often, especially once that OMGPOP has a chance to build on the success of its first endeavor with Zynga's deep pockets behind it.
Give the PC version a whirl with the PC demo, which you can download here from Shacknews.