I keep savannahs, which in a lot of ways are a whole different kettle of fish. However, I've run into a bunch of websites with bad monitor care info as well as a few good ones. Here are my recommendations:
www.mampam.com has a species account of varanus niloticus that covers some of Daniel Bennett's observations and advice on captivity (he basically says "Don't bother," but then gives a little bit of information about what to do with them in captivity).
www.varanus.net has a forum dedicated to captive monitor care. It can be a little bit hostile to newbies, but if you can prove a dedicated interest and have a thick skin, there are plenty of good people who give good advice.
Also take a look at nessiesmom.freeservers.com. This is a site run by a couple who had some extraordinarily tame nile monitors. Sadly, most of the monitors are no longer alive due to a viral infection that swept their collection. The site and the tips still live on, though.
I won't assume anything about your level of experience or dedication, but I do hope that you know what "large and aggressive" means in terms of monitors. I've seen/tried to handle subadult niles before, and I consider myself lucky to still have all my limbs and digits attached. These guys have claws for days and a nasty tail-whip when they feel like their life is in danger, which for most of them seems like all the time. However, if you're really okay with that (with a username like "burmer" you probably understand what caring for potentially dangerous animals means), I've been told that niles are beautiful display animals.
Hope this helps.
Des Harmon