Updated Thu, Feb 21, 2008 by DarkFact
The Wintersabers are one of the most elusive and hard-to-get 100% speed mounts in the game even now - this is an Alliance-Only questline that involves a lot of time and effort dedicated to killing monsters in Winterspring.
As mentioned, there is no Horde equivalent to this Faction. It is rumored the Un'goro Raptor Trainer was going to be the one to be for the Horde but Blizzard never confirmed nor added any quests for that NPC.
To begin your quests, head over to Frostsaber Rock in Winterspring and talk to Rivern Frostwind - he will start you off with your first quest. You will begin at Neutral with the Wintersaber Trainers.
You will obtain the first quest - Frostsaber Provisions, which will ask you to retrieve 5 Shardtooth Meat and 5 Chillwind Meat for the NPC. These can be obtained from any Bears and Chimaeras in Winterspring at a very low droprate. Once you turn this in, it will be 75 reputation.
Upon reaching 1500/3000 Neutral, another quest will be available for you, called Winterfal Intrusion. This one asks you to kill 5 Winterfall Shamans and 5 Winterfall Ursas (this will also help you bump your Timbermaw reputation up!). Each turn-in will net you 75 reputation as well.
While repeating the first two quests, you will unlock the third and final option - the quest Rampaging Giants. Heading south you will need to kill 5 Frostmaul Preservers and 5 Frostmaul Giants to complete this quest.
While you may think doing all 3 is the fastest way, due to the nature of these quests, it might be best to focus on the Furbolgs or the Giants exclusively so you don't spend more time out than you should.
It's worth noting you will not receive reduced reputation penalties if you attempt this grind at level 70.
Frostsaber Provisions (Neutral) - 75 Reputation (Good until Exalted)
Winterfall Intrusion (1500 Neutral) - 75 Reputation (Good until Exalted)
Rampaging Giants (Honored) - 75 Reputation (Good until Exalted)