The Riding Crop is a new Leatherworking pattern added in The Burning Crusade, which works as a 10% mounted speed increase up from the 3% Carrot on a Stick from Vanilla WoW.
The difference with this new trinket is that it no longer stacks with similar movement speed enchants, which means there is no longer a need for multiple sets of gear to run around in like many players did in Classic.
While the Riding Crop is a leatherworking crafted item, it can be traded and sold so all players have access to it.
How To Craft The Riding Crop In The Burning Crusade Classic
Players can buy the pattern from Thomas Yance, who can be found traveling around the Old Hillsbrad Hills dungeon.
To craft this item it will require 4 Heavy Knothide Leather, 6 Arcane Dust, 1 Small Prismatic Shard, and 1 Primal Might.
Because this item requires a Primal Might, the price will always stay relatively high as they will always hold somewhat of a value.
Players can alternatively just purchase the Riding Crop from the Auction House but may spend a little extra than farming the mats or buying them at cheaper times.
There is a similar item called the Skybreaker Whip, rewarded from the quest "Dragonmaw Race: Captain Skyshatter" as part of the Netherwing reputation, although can be quite a tough quest to complete and the Riding Crop is not very expensive in the long run.
There are no more move speed increase items for the remainder of TBC so getting it early is a huge benefit and will make a big difference no matter what you are doing in the open world.