I watched episode 1 last night. It's very silly but seems like fun. There was also an error in the episode, with someone winning from a hand that isn't a real hand or something like that. Well I only decided to watch it after seeing pictures of Saki posted on /a/, so I'm not complaining.
Apparently, this is a really good tutorial; should go well with the Saki-themed rules above:
http://v3gas.navhost.com/mahjong/
A mahjong program for Windows (in Japanese). Has lots of settings:
http://rapidshare.com/files/60276460/Saikyo_no_3D_Mahjong-JP.rar
A flash game in English. Seems a bit confusing to me because it doesn't show the wall:
http://www.gamedesign.jp/flash/mahjong/mahjong_e.html
An online mahjong site where you can play with others. /a/ would go on here all the time when Akagi was airing:
http://tenhou.net/
You have to click on
Play and then on
サーãƒã«æŽ¥ç¶š, which takes a few seconds to appear. There's a lot more info on it for English speakers
here. Once you've got the basics, this is probably the best place to play (other than IRL with friends, of course). Apparently the players aren't that great or anything, so you shouldn't be intimidated.