No not yet, it’s still in development. In the FAQ section they say they’re hoping to have an alpha at some point during 2009, and they have released a combat prototype which I’m downloading from here
The Infinity Combat Prototype (latest version: 2.2.a) is a standalone game that has been released and improved upon the past months, as a way to test many components of Infinity before it is finished.
This is a completely separate program that only shares the engine. It does not represent what you will find in Infinity. Its goal is, namely, to test: the graphics engine, the physics engine, the networking engine, experiment with controls / combat mechanics / balance, to improve stability/fix bugs and measure/stress performance.
The combat prototype is not meant to have a deep gameplay; do not expect any form of planetary landing. 10 ships are available to the players. The gameplay is arena (team vs team) based, while Infinity will be a fully open “sandbox” type of game.