Media & Press Visa
There are two types of Media Visa's in Thailand as follows:
Short Term (For specific events, less than 90 days)
Long Term (Up to 1 year, renewable)
You must allow about 1 full month at least to go through the application process. Below are the various links that will guide you through the process. Be aware that you need lots of documents.
This application goes through your own embassy. I have used the New Zealand Embassy website as an example as the process is not fully explained in all countries Thailand Embassies websites.
http://www.thaiembassy.org/hague/th/services/76471-Non-Immigrant-Visa-M-(Mass-Media-of-Communication).html (Good guidelines)
http://www.thaiembassy.org/main/ (Find your Thai Embassy here)
This application goes through the Ministry of Foreign Affairs and they have a online-website specifically for this process.
http://mmos.mfa.go.th/ (This is the Online Registration site)
http://mmos.mfa.go.th/process/ (This page tells you the process
http://www.mfa.go.th/main/contents/images/text_editor/files/Guidanceforforeignpress.pdf (Guidelines and check-list)