Next summer, we're going to Thailand for 18 days. Any good advice about this country? We're travelling with an organisation.

Yeah, read up on Thailand ahead of time and have a good idea of what you want to see. If your organization is a tour group I guess your moves are already planned.

If you have any input into deciding where the hotel will be located - see if you guys can get a hotel on the Skytrain route. The Skytrain is an overhead rail service that can bring you around the city pretty easy and cheap.

Change your money over after you get to Bangkok for the best rate of exchange. There are banks at the airport for changing money. ATM's are available too. If you use an ATM for cash withdrawals make sure you notify your bank first that you will be in Thailand or the withdrawal may be denied.

There are meter taxi cabs available at the airport 24 hours a day. Avoid the touts in the arrivals hall that are selling rides - meter taxi desk is outside near the curb. Have small bills available when you pay taxi drivers, a 500 baht note may be too large for a driver to cash. Often drivers say they do not have any change, hoping you will be stupid and say "keep the change!"

More info links:

http://www.tripadvisor.com/ShowForum-g293916-i3687-o20-Bangkok.html

http://forum.virtualtourist.com/forum-1943-1-Travel-Thailand-1-forum.html

http://www.lonelyplanet.com/thorntree/forum.jspa?forumID=51

Good luck.

If you want to go to Khao San (Banglumpoo) from the airport take a free shuttle to bus station and then bus 556 (about 40baht) to Khao San.
If you want off the beaten track...visit Loei and Nan in the north...lots of natural environment and cultural mix of N.Thai(lanna) and Lao. In the south visit Kuriburi, Phang Nga...gateway to Surin Marine National Park and the most spectacular snorkeling and diving in Thailand. Kuraburi is surrounded by Thai terrestrial and marine national parks and is home to Moken Sea gypsy people.
Indian Ocean Adventures