Laos, which also all Thai will call less developed has now for almost 1 year a fully working 3G network. It is not the fastest in the work but it works pretty good, it is surely faster then what you can get in Thailand with GPRS/EDGE.
I can download screamed video and it never hicks, get corrupted... pretty good..
I read in a Thai newspaper that the decision for the 3G network licenses are again delayed... M-Phone the Laos provider of the 3G network is already working on the next Generation... Maybe Thailand can just skip a Generation of telephone network development.