I used to have really dark hair on my arms because when I was 5 years old I decided to shave my arms ha ha after seeing my mum shave her legs.
And through my life I have had dark arm hair and was self conscious of it also, but then I realized if a guy is going to judge me on some hair on my body which by the way is completely natural then he must be a right d***.
I now bleach the hair on my arms,for me it works perfectly and also for the hair on my body, but I do it for myself and my confidence not for anyone else.
Always be careful though with bleaching, and when I mean bleaching I mean special peroxide that is meant for body hair :)
For every possible thing out there, there's a guy (or girl) who's into it. I'm not sure why, but often light hair on a girl's arms turns me on. At best, it's not an issue. As happyangel said, if a guy really is that shallow or neurotic, he's an a-hole you don't want to be involved with anyway, as he'll continually pick at your tiny, perceived "flaws", while being less than a perfect specimen himself.
So relax, it's either 1) not an issue, 2) actually a good thing, or 3) only turns off jackasses so also a good thing.
Unless it's particularly thick, or you have, like, very, very dark hair and very, very pale skin, it shouldn't be an issue for the vast majority of guys. I don't think there are many guys out there that want everything to be completely waxed. That's pretty weird.