As the PP said, it's not clear if you're asking about at the resorts or at the parks.
At the resorts, it varies by resort, but at the Boardwalk and Beach Clubs, there is only one stop. All buses go there and you just have to read the digital sign on each bus to determine where it is going.
At the parks, there are signs as you approach the bus stop that tells you what number to go to. Typically the names of the resorts are also listed at each stop (but I can't remember if that's true at all parks). The stops numbers can change, but here are a few pictures of the bus signs for Epcot (2009) and Animal Kingdom (I think also 2009).