It's been announced Plants vs Zombies will arrive on XBLA come September 8, which is a couple weeks earlier than the previous "fall" release announced last month - at least for the UK.
According to IGN, the US gets it on September 28, which is indeed fall.
It includes seven game modes, including two all-new multiplayer modes, 12 Achievements and 21 mini-games.
The game will run you 1200 MSP/$15.00/£10.20/€13.96.
We'll confirm the US date with PopCap just to be sure.