The first game in the series (developed by BioWare) was released to critical acclaim in July 2003 for Xbox, and later for PC. KOTOR came to Mac via Steam just a few months ago. Obsidian developed the game's sequel, which launched on Xbox in December 2004.
We've reached out to LucasArts for more details on the collection.
Update: The game is listed on Amazon as Star Wars Knights of the Old Republic I and II PC Bundle Pack, and is available for preorder. We are still confirming details with LucasArts.
Thanks for keeping those eagle eyes sharp!