That answers all of the questions I had in the last related news post.
The game should take up at least one gigabyte of space. Other free-to-play shooters such as Quake Live, Battlefield Play4Free, and S4 League take up 700+ MB on the PC. Then again, it might be a leaner cut of the PC version. Battlefield 1943 (XBLA, PSN) clocked in at ~350 MB with 4-5 maps.