So in season 5, episode 8 of supernatural we find out something about The Trickster...
Believe it or not, he's the Archangel Gabriel
So I was wondering, how did he know Sam and Dean were 'in town'? Did he lure them to that town then?
The opening of the episode shows that Sam and Dean actually tracked the Trickster to the town, and not the other way around.
They were investigating a case where a woman claims her husband was murdered by "The Incredible Hulk", and figure out that it's The Trickster behind the deaths. Once they start to chase him down, it would have been easy enough for him to figure out that they were asking questions in town, etc.
Given who we learn The Trickster is, and how he's related to the Season 5 plot, it seems very likely that this was actually a trap set for the brothers. He must have expected them to hear about such a bizarre murder and come to investigate, where he had the trap planned out. (Presumably, if another hunter had shown up, The Trickster would just have moved to another town and tried again.)
He is one of the most powerful beings in the universe, as near as I can tell. At the top, we have God and Death. Below them are the leviathans. And below (equal to?) them the archangels, of which only four have ever been portrayed. While still weaker than both Michael and Lucifer, it should not be forgotten that Gabriel is a being that could single-handedly wipe out all of the pagan deities. Probably without breaking a sweat.
Though Sam and Dean are hidden from the angels' limited omniscience via the rib sigils, Gabriel and other angels can see both of them if they happen to focus their presence on a particular region (Castiel once searched an entire town for a trumpet in just a few seconds). Gabriel's not dumb either, by any stretch of the imagination, and luring and/or following them wouldn't be tough.