Halo: Spartan Assault was a Verizon exclusive in the USA for 30 days, and those 30 days are now up, meaning we can expect the game to arrive on handsets on AT&T, T-Mobile and Sprint in the next few hours.
Unfortunately we have not heard that anyone has successfully installed the app yet, but if you are the first let us know in the comments below.
Update: It seems it was 30 days inclusive. We are now getting reports that the app is now finally downloading and installing! Find the game at the links included.
Try your luck in the Windows Phone Store here.
Thanks Aaron for the tip.