I found an easy to get underneath Drak'Tharon Keep for fishing purposes (musselback sculpin, dragonfin angelfish, and glacial salmon can all be caught here)
Start Here:
WoWScrnShot_021010_184029.jpg picture by s34n42 - Photobucket
WoWScrnShot_021010_184036.jpg picture by s34n42 - Photobucket
Position yourself here, so that you can't move any closer to the wall
WoWScrnShot_021010_184114.jpg picture by s34n42 - Photobucket
Mount up and use the DC macro to get inside the wall(this requires a fairly large ground mount. I did it with my polar bear, it did not work with my cat)
WoWScrnShot_021010_184316.jpg picture by s34n42 - Photobucket
Now Jump and move forward a few times, sometimes have to play with your angle slightly
WoWScrnShot_021010_184324.jpg picture by s34n42 - Photobucket
WoWScrnShot_021010_184335.jpg picture by s34n42 - Photobucket
Once you get through, you can mount up on a flying mount and fly around inside the walls and underneath DTK
WoWScrnShot_021010_184345.jpg picture by s34n42 - Photobucket
Dragonfin and musselback can be caught here, your location will show as Drak'Mar Lake
WoWScrnShot_021010_184426.jpg picture by s34n42 - Photobucket
Fly over here and your location will be Grizzly Hills(Drak'Theron Keep), you can also catch angelfish and sculpin here, but to the left you will be able to catch glacial salmon. If you stand where I am in the screenshot, and angle yourself just right, you can catch all of these fish from the same location.
WoWScrnShot_021010_184436.jpg picture by s34n42 - Photobucket
WoWScrnShot_021010_184509.jpg picture by s34n42 - Photobucket
You can also get your bobber to land on the angeled waterfall there which is kinda cool(you only catch salmon in that direction) I am quite certain nobody can see you here, I also use aspect of the beast making myself untrackable