Translated details of the 3DS version of SSF4's Street Pass mode were posted by AndriaSang.com. The real fun of the game's figure component comes in its Simulation Battle mode. This uses Street Pass to pit your figures against figures of players you pass by on the street in automated battles.
The Simulation Battles require a bit of set up. You have to initially create a team of five figures who will represent you in the battles. When adding up the level of all your team members, the total level has to be 20 or less. Once you've created a team, you can distribute a preset quantity of points between your figures' Power, Defense and Speed parameters. These points add to the values that are set in advance from the figure's level.
Also, TheGamingVault has a hands-on preview of this title going over how the various features work. It's written by someone who understands fighting games and talks about the title logically, although he's discussing things you've probably read about else where, it's nice to hear about them from this perspective. Here's another clip.
I actually am looking forward to street pass mode. I don't know why but I loved collecting those little trophies in smash brothers, and it'll be the same with collecting Hakan figures.
StreetPass somehow sounds so... RPGish
I like it :D