Thailand and Cambodia share a border, and recently there has been tension involving the Preah Vihear Temple, which was declared a world heritage site in July of 2008. The temple itself is apparently in Cambodia, but the area around it is in dispute. Both lay claim to much of the surrounding area. Cambodia bases its claims on maps created by France when it colonized Cambodia, while Thailand supports its position with evidence of watershed. In any case, both countries have placed troops along the border. There may have been some gunfire, but there is little chance of a real war breaking out over the area.
It is widely believed that Cambodia Prime Minister Hun Sen appointed Thaksin as an economic adviser to tweak Thailand. Its certainly worked in getting people talking. Thailand requested that Cambodia extradite Thaksin to Thailand when he arrived in Cambodia, but the request was refused. Thailand refused to let Thaksin's private jet enter Thai airspace on his return trip home. Cambodia arrested some Thai employees at the airport whom they accused of spying for Thailand in trying to get information on Thaksin's flight.
While Thaksin made it safely back to Dubai, I'm not sure these latest moves won't hurt him. Thai people are very nationalistic and proud of their country. At best, Thaksin seemed to have allowed himself to be used by Cambodia in their dispute against Thailand. At worst, some may believe that is he choosing to help Cambodia against Thailand. If Thai people start believing that, I think his support will fade even more rapidly than it already has.