This works for both horde and alliance, though horde need speed pots + any mount with 60+% speed.. FOR ALLIANCE - Go behind the alliance base and there should be a slope sticking out, get up on it slightly and then you can wall jump or MC to the back of it, then wall jump so you are on front of it and jump on the ally roof. If you want to be safe use a mount for this next jump, or just wall jump to a higher point on the roof first. Now, run across the roof (to the right if you just jumped from the slope the roof in first person) and jump over the gate! Gratz, I was ticketed with a warning after doing this like 600 times, so just don't do it every AB, I'm thinking a horde reported me lol..then I got banned from some trouble I had in Hyjal. Ok now for the horde guide...
FOR HORDE - This is a bit more difficult, bring a speed potion (or dash\speed buff\slow fall) Ok go right around the back of the horde base, you see that slope sticking out? Wall jump the LEFT side of it(looking straight at it) When you are at the top\flat area where you can run, drink your potion or jump with slow fall over to the roof of the base. Now go to the other side of the base, do you see those wooden planks around the area you exit the bg? Well look at the left corner of them, this is quite easy with slow fall to jump from the upper part of the roof, but for normal people run with your mount and jump into there and then run\jump up the side. When you are on top of the 2nd or 3rd (I don't do this much on horde) block of wood, walk along the side and you should be able to come down right behind the gate, if not jump over it.
Sorry for the lack of details in the horde guide - Pics below.
Alliance spot to jump - (Red lines are the 2nd way to do this, green is the easier 1 I just explained)
http://img218.imageshack.us/img218/1...hibasinjt8.jpg
Horde spots -
Pic 1 - http://img357.imageshack.us/img357/1...epicab1es5.jpg
Pic 2 - http://img357.imageshack.us/img357/9...epicab2wh8.jpg
Note, circles are places to land.
YES My desktop is loaded, I need to clean it some day :P.