I haven't completely overcome arachnophobia, but I have become more tolerant and less reactive.
I used to freeze so much I couldn't even say the word 'spider' to tell people what was wrong. Maturity progressed this into at least saying '8 legs' and pointing to the offending creature.
Since having kids, I figured that I had to be brave so not to pass on my fear. Now I am able put a glass over them & wait for OH to get home, or if smaller than 5p piece I can put something under the glass and flick them into the garden.