I've generally had good luck finding this at Asian grocers... It can be used as the base for the kind of Thai tea you get from a restaurant, just add sweetened condensed milk. I'm not a huge sugar fan so I drink it straight. Even then, it has a nicely bold flavor, and an incredibly high caffeine content.
Oh my bad, my reading comprehension seems to have stopped at "sweetened condensed milk". Thanks for the tips though, appreciate it!