If your going for the all inside watercooler, you will have to use a radiator that fits into the front part of your case where the two 80mm fan holders are. The Extreme looks to fit as does some heater cores (can be found at junkyards pretty cheap).
You usually have to mod the front panel to remove any excess metal so that there is no obstruction of air. In other words get a dremel or I used a $10 nibbler from Radio Shack, to remove the place where the radiator needs to set. I left enough metal to mount my radiator to it. Then the radiator goes in and the fan will draw air through it into the case.
(Only disadvantage of this is tepid air is going to be used to cool your other heatsinks, but really has never been a problem for me).
Mounting your pump (reservoir if your going to use one) should be in as out of the way place as you can get, but I didn't have any room so I have it right in front of the radiator. (Several inches away, so it doesn't block airflow).
The bigger radiators usually mount on standoffs (the same kind of thing that you use to mount your mobo, but bigger) on the back of the case. This really depends alot on your case as to how it really will work best. You can also mount it on the top of your case and just elevate it slightly off the case so it is drawing outside air through the radiator. This way there is no radiator air going into the case, but it obviously looks kinda crappy. If you have space for a second box somewhere you could mount only quick disconnects (for the tubing) on the back of your case and from them just run the tubes for your waterblock. If you use valves behind the other side of the quick disconnect you can remove the tubing without spilling much water at all and remove alot of leak possibilities from inside your case. The rest of the watercooler can sit in a small computer box or basically anything that you can mount an old spare AT power supply in (to power your fans for the radiator) and the radiator and the pump. If your using a bigger pump like the Eheim's the extra tubing won't be an issue.
If you confused about anything I will try to answer to the best of my knowledge but if you just want more reading material about watercooling I would suggest
Overclockers.com. They have alot of really good articles.