Either way (self extracting or not), the first thing you'll have to do is to remove the "bolts" that keep the cranks on. 8mm.
If the cranks were self extracting, they'll come off in the process of unscrewing the bolt.
If not, you need a crank extracter. Park tools sells one. I've used it for Campy square taper, Older Shimano square taper and Octalink/Isis style bottom brackets.
http://www.parktool.com/products/detail.asp?cat=26&item=CCP-4
What is interesting is that Park says that tool won't work on square taper, however that is bogus as i've done it many times, including just today! You just need to remove the "disk" that is screwed into the end of the tool. I've not noticed any damage caused to my BBs either.
Also, watch the knuckles when doing the drive side. I got some nasty gashes last year doing this. Those things are probably torqued on there pretty good.