Well, I've never had this problem because I've ALWAYS been in love with spiders, but I think that if I were trying to overcome a fear of any animal, I would try to learn as much as I could about that animal, such as how it acts when threatened and whether it is a threat to me, etc. When I saw it, I would think about these things and just observe it, trying to ignore the natural fear response. Try to see how utterly beautiful spiders are, because they really ARE beautiful. If you can see that, then maybe you wouldn't want to kill them, and instead you would want to merely watch them and then take them outside or something.
Note: the venomous ones are NOT the right ones to just pick up and take outside. Haha. If you find a brown recluse or black widow, I would not recommend trying to mess with them. Haha.