I've had dreads for about six months now and I was wondering if it was possible to dye them. If so, is it any different to dying normal hair?

You can dye them.
Be super careful if you need to bleach since bleach is damaging to hair and you don't want your dreads to disintegrate.
If you use wax, dye your hair at a time when it needs re-waxed so that the dye can soak in more easily. Just bleach and dye as normal. You need to make sure to rinse it really really well though. I'd suggest leaving the roots alone in case you get breakage there.

I cant reccomend this article by Lishd I found on Get_up_dread_up enough:-

http://www.compunction.org/dyeing.txt

It really is ALL youll ever need to know!!