We found our Thai language school while visiting Chiang Mai last spring. Yai at http://www.easystudythai.com/ has been very helpful with answering our questions about the class and how the student visa process will work. By getting a student visa we will be allowed to stay in Thailand for an entire year. We only have to renew our visa every 90 days at the local immigration office in Chiang Mai.
We are now awaiting the necessary official documents from Yai so that we may send our application to the Thai embassy. This may sound like a bit of a hassle, but we believe it will be easier than landing in Thailand and then having to leave the country in order to get the paperwork completed by a neighboring country's Thai embassy.