The Explorers' League is one of the reputatios involved in the Alliance Vanguard. Explorers' League has one daily quest available to it, to help you raise the reputation. It does not have a quartermaster or any rewards for raising for the reputation, just the satisfaction of you knowing you did it. Below is the daily for raising your reputation with the Explorers' League.
Additional Note: As of patch 3.3 you will gain Explorers' League Reputation in all Northrend Heroics. The amount of reputation you gain is minimal and will not display unless you have reached exalted reputation with the Alliance Vanguard and The Silver Covenant.
Steel Gate Patrol
Steel Gate Chief Archaeologist can be found around 30, 26. Accept the daily quest from him them kill 8 of the Gjalerbron Gargoyles flying around the large pit nearby. You can use the flying machine or round them up by flying around yourself, It's your choice. The flying Machine is nearby the Steel Gate Chief. Also don't forget to loot the Gargoyles after you blast them down.