World-of-warcraft – World of Warcraft Mount Purchase

Warlocks do not get special class specific flying mounts. Instead, you can buy a faction specific flying mount from a vendor which should be located somewhere near the trainer who taught you flight.

For instance, in Stormwind, on the platform where the flight trainer is located, the mount vendor is the third NPC on your left (just past the flight master). He should offer griffons in a variety of colors.

For the sake of completeness: Here is a list of all Flying Mounts, click on any one to see where it is obtained. Most of those are Epic Flying mounts that will require you train 300 Flying at a cost of 5000 gold. For 225 (Expert) Riding, This is the entire list. Note that the Broom is a limited duration holiday item, the X-51 Nether Rocket is from the trading card game, and the remainder are faction specific.

Listed here, you'll find the 5 vendors that will sell the three mounts you can use right now. They're located in Stormwind, Dalaran, Honor Hold, Valiance Keep, and Wildhammer Stronghold in Shadowmoon Valley.

You can find detailed information on available mounts at WoWpedia. I'm not going to list all available mounts here, but you can find them all at that page. I'll try to summarize the general approaches you can take to getting a more exciting epic flying mount.

Basic wyverns are available from vendors when you hit level 70 and buy the Artisan (300) flying skill. Other mounts like the various drakes are typically available as faction mounts or rare drops.

Some are boss drops such as the Bronze Drake, others are reputation rewards such as the Netherwing Drake Mounts or the Red Drake. If you're a tailor, you can craft a flying carpet or its winterized version. Engineers and alchemists can also create flying mounts for themselves.

You can also buy this blue wind rider from Dalaran, but it's not terribly different from the common mounts except in colour.

Last but not least, there are mounts like the Violet Proto-drake that are awarded for getting certain achievements.

As you can see, the list of options is long and varied. Since you're nearing level 85, pretty much any of these should be available to you at least as far as plain level requirements go. Which mount you should go for first depends entirely on what you feel like getting and how much time/gold you're prepared to spend to do it.