Originally Posted by dabac

Well, no.
All threadless forks aren't interchangeable.
1 1/8" is a quite reliable standard. But first the fork needs to have the right steerer tube length - or longer - to be possible to fit it to the frame.
Then the fork legs needs to be right too. The axle-to-crown distance needs to be about right, and the rake - forward extension - needs to be about right too.
Then the fork needs to be compatible with the brake type you intend to run.
Dropouts have to match the axle type in the hub you want to use.
Width by fork crown needs to allow the type of tires you want to use.

But yeah, all forks with 1 1/8" steerers should be able to use the same headset.