I'm thinking about taking my group into the bowels of coruscant. Has anyone done this with their campaigns? If so what resources did you use and what was your adventure hook? I'm drawing heavily from the concept art for 1313 and all obvious source material I can get a hold of. Tips from those that have run campaigns like this would be most appreciated. I'm going to jaquays the crap out of my maps and possibly reuse this module in the future. If there's a source of pre-generated scifi city maps out there I think that would be very beneficial because I don't think I'll have the time to draw it up myself.
help with coruscant ideas
You play the free module?
It's pretty much what you are looking for if you haven't.
Also check out some things like Blade Runner or Judge Dredd (the comics or the Karl Urban movie, not the Stallone one) for some dystopian mega-urban inspiration.
I'd also advise watching TCW, there are several episodes that take the characters into the lower levels. The last four episodes of season 5 are particularly detailed.
What does it mean to 'jaquays' a map?
I would stick with themes; you can describe twisted cityscape only so many times. If you focus on specific locales and make sure to throw on something touching on how little sunlight penetrates the city layers above, or the constant musty dampness, the squalor and the crowding, they really help give it a flavor of undercity.
Make something like the Dancing Duro - the walls are the same peeling paint as when the place got its name, and nobody remembers when or why that was. The only time it gets cleaning is when the reservoir above it springs another leak, flooding the area and leaving swampy puddles for days. Eventually you can no longer tell the race or gender of the creature at the next table, and the anonymity is why folks patronize it - it certainly isn't for the beer.
You might find some good inspiration if you swing over to the Dark Heresy support page and read through the stuff on the Lower Hive, then add more aliens. There is a (un)surprising amount of similarity between lower 40k hives and lower coruscant.