You're gonna need a LOT of patience, a very sturdy metal comb (o even more than one, depending on how tight your locks are), and some kind of conditoning agent...I just used plain old hair conditioner nd it worked fine...BUT be assured, using Olive Oil, Conditioner, whatever...you are STILL gonna need to expend a LOT of elbow grease...seriously, I would suggest, if you're gonna chop it short anyway, cut your dreads to a little longer than what you're gonna eventually want length-wise...This is what I did with my last set of dreads, Cut them all to about 4" from my scalp...and even those 4" dreads took 4 hours of solid work to comb-out, and an entire bottle of conditioner, and broke my metal comb in a number of places, and gave me handfuls of blisters...

Good luck :) xx

oh man...i feel you on this one. i de-dreaded about 6 weeks ago.
my remedy:
one very ADHD hair dresser, about 6 hours, and a post-combing bicep massage.

she used a plastic comb actually, despite how incredibly tight my locks were. she broke 2 teeth off of it, but i'm sure the process would go quicker with a metal comb. my locks were very clean, only some [unfortunate] wax residue at the tips from when i first started them.
she cut off the bottom inch, loosened what she could from the bottom up with her hands, then from the bottom up combed out about a centimeter at a time until she got to the roots. no conditioner, no spray, just patience, elbow grease, and lots of distracting conversation.
your scalp will be pretty sore if you use this method, but in a few days, everything will be baseline again.

take care, much respect.

For those of you who have recently combed out your dreads... how long were they?
I've been off and on about combing mine out sometime in the next year (at the moment I've decided that I'm not ready to part with them, but I'm still curious). Mine are lower-back length, and I'm wondering how much i'll have to cut off when the time comes.

NOOO dont chop it out!!!! Alright I've been through this 2 times...conditioner OVERNIGHT...lay it on thick!!!!! And then just fiddle with them the next morning. Or if you dont want the really stiff hair dump conditioner on your head in the morning and then finger through them after dinner while watching a movie or something...do it absentmindendly other wise you going to get really flustrated. It will work it will be really frazzled but more conditioner works...when you get it all taken out take a shower. Shampoo...MORE conditioner leave it on over night and then wash in the morning...enjoy the dread freeness. Trust you will miss it though.

To take them out, I suggest 2 bottles of conditioner, the cheap kind. Dont worry about the brand,
you just want it to oil up your locks.
If your tips are tightly locked up, you might have to snip em off a bit,
and face it, when they are out, unless you wanna look like a frizz ball,
your gunna have to cut the ends anyways because your hair is going to be super dead.
When I took mine out, I mainly used my fingers.
I wanted to salvage as much hair as I could so I avoided the combs.
One by one.. piece by piece.. Was left with hair a bit longer than shoulder length.