Asia TEFL has been spreading its wings since about 2003, and now has more than 12,000 members (which would have to make it one of the biggest ELT associations in the world - as befits the region in the world with the largest number of EFL students, I guess).
There are three things I quite like about this organisation:
2. The move their conferences around the Asian region every year (China 2005, Japan 2006, Malaysia 2007, Indonesia 2008, Thailand 2009), making them truly representative of the region they profess to cover (unlike so-called International associations like IATEFL and TESOL, which always only ever hold their events in Britain or the United States resectively). They also get some very big names to their events!
3. They offer up to 30 travel grants of US$300 to presenters coming to their conferences. So not only is their membership free, they really do make an effort to help out the people who decide to participate as presenters at the events.
My only concern or criticism is that the organisation is extremely academic and policy-driven, which can often make "your average teacher" feel somewhat excluded. I hope as an organisation they can learn to cater to the practical and pragmatic considerations of teachers in the region, and avoid the risk of becoming like a bit of a "gentleman's club" - only welcoming people with certain faculty positions or lofty pieces of paper in their resumes.
Then again, teachers can do something about this as well, by getting involved and bringing the practical and pragmatic presentations I mentioned to the Asia TEFL events. Sometimes we're only "excluded" if we allow ourselves to be!
The next conference will be held in Hanoi, Vietnam (August 6-8, 2010). The call for presentations is now open, so if you're Asia-based, consider becoming an Asia TEFL members and presenting at (or attending) their next major conference!