Sony have announced an updated version of Tekken 5: Dark Resurrection with support for online play:

The new TEKKEN(tm)5: Dark Resurrection Online download will include Opti Match , Quick Match, Custom Match and Friend Match options - making it easy to find the right match for you. You'll also have the opportunity to study your opponents by viewing their stats and watching them battle. When not fighting yourself, you can psych out your next opponent with live voice chat. You'll fight your way from 'Beginner' rank all the way to deadly 'Dark Lord' - and there will be an Online News Ticker posting the weekly, monthly and overall rank leaders at any given point, so there will be no doubt about who's King of Iron Fist at any one time. The online update also includes two new single-player modes, including Practice Mode, where you can hone your reflexes before battling online, and Survival Mode in which you must defeat as many opponents as possible with a limited health bar.

The press release implies there will be two versions - one from the Store which any user can buy to just play the game online, and an update for those who've already bought the game which will add online play (one would hope that it'd be free, but there's no mention of that in the announcement.

i'd imagine fighting games would suck online? Anything less than an instant connection would suck wouldnt it?

I don't know, but it seems like they'd suffer from similar problems to FPS games - if the response time from when you press the button and when the action is processed by the server is too long it's surely going to be laggy schlock. I suspect client side prediction isn't so useful in a fighting game as well.

I don't know, 150ms was good enough for quake,

64 bytes from 130.102.2.20: icmp_seq=4 ttl=51 time=31.504 ms
64 bytes from 130.102.2.20: icmp_seq=5 ttl=51 time=32.539 ms
64 bytes from 130.102.2.20: icmp_seq=6 ttl=51 time=27.841 ms

The Japanese have been playing SF2 on kaillera with MAME for yonks!

What about SF2 on live! ? It's not like a 1v1 fighter would suffer the same inherent lag issues a 16 player FPS would.

doa4 on xboxlive i found was ok when playing agaisnt people locally, soon as you went overseas though it went abit sour, i figured it was normal and that you dont notice it with fps as badly.