I am the author of
Read Thai in a Day. It's a downloadable interactive e-course. It does sound a little far-fetched, doesn't it? Nevertheless, it only requires a few hours to master the Thai alphabet and the tone system if you use the visual-thinking and memory-association approach upon which the method is based. (As in "Men in Black 2", the brain does require time to "reboot" as it were. You also do need to allow time for the information to "percolate" in your brain, so the recommended method is to complete the course over two readings at least a week apart, and refresh it all a month later.) Please visit
http://www.learnthaionline.com.
I am plugging my system because (as most Thai teachers and experienced learners will tell you) I realized that in order to learn Thai quickly and effectively, it is absolutely vital to be able to read Thai from the beginning.
My advice to anybody wishing to learn Thai is to learn to read first - buy my system - and then sign up with a school or a teacher who will jump straight into Thai reading and listening. AUA follows an immersion approach, but I don't think it's effective on its own. Their idea is to put you in a class which is just beyond your level of comprehension, so that your mind "stretches" into the language, as it were. This is how children acquire a language. But we are no longer children and our brains function in different ways. (I'm currently doing Masters/Doctoral research on this issue, so I'm still trying to find out for sure...)
So buy my course
Read Thai in a Day and then buy the bilingual storybooks,
Winne The Pooh, Noddy, etc. (I will send you a recommended reading list after you've completed the course. Work through the books (reading out loud) with a Thai teacher who can explain why sentences are written the way they are.
(I did previously suggest
Thailand Fever, but the translation is very idiomatic and not suitable for absolute beginners. I would, however, highly recommend it as a way to help you as an intermediate student to achieve fluency in Thai!)
Children's books use quite flowery language (and when will you enter into a discussion about witches and goblins anyway), but there are some books for young readers that are quite relevant. Very soon, within a few months, you will be able to read stuff that interests you personally. It's more fun to learn Thai this way, as opposed to learning "standard" phrases from a grammar book. Magazines and newspaper articles are too technical/advanced for a beginner.
I personally find Rosetta Stone extremely dull and repetitive. One of the very first words learnt is "bicycle", not something one would talk about when one first comes to Thailand...
The Pimsleur audio course is quite good (albeit very rudimentary and a little dull) for developing an "ear" for Thai and for practising to speak with a good, clear accent. It is important to repeat everything you hear in the course in an exaggerated manner. You should practice reading aloud also. Speaking properly requires muscle training, just like learning to dance.
There is plenty of research that shows that reading is the most effective way (for adults) to develop competence and fluency in a language (e.g. Stephen Krashen). In my own research, I've discovered that you can only really
hear what you already understand.
The phonetic approach to learning Thai commonly used by most beginner books and schools is severely limiting and usually leads to learning an incorrect version of Thai. At best, you will end up learning a kind of mangled Thai that only Thais used to tourists will understand (in which case you may as well stick to English). You will quickly reach a ceiling beyond which you will never progress without having to start again from scratch. It's why most foreigners give up...
The Paiboon books are okay, in that they are fairly thorough - but also quite dull. If you want an introductory language book then I highly recommend
Everyday Thai for Beginners by Wiworn Kesavatana-Dohrs. The unique feature is that it does not use phonetics.