Well, most of the sites that cover civ2 cover civ3 as well, and mods/scns will of course be very important. I have no doubt that there will be enought sources on the web for this stuff.
And yes, due to the lots of gfx (or even anims) civ3 mods/scns will be much bigger...can be a pain for downloading it with only 56k

However, as long as the mods/scns are great