iPhone Tweak to override http links to other Apps
There's a JailBreak tweak called Browser Changer, and it does almost exactly what you want. It's in the standard repositories in Cydia, and it's free. I've used it to make all links automatically open with Dolphin Browser. It works quite well, but it can only make one app open all http links, so other than that, there isn't anything that does exactly what you want.