Hmm... MSVC toolkit plus platform SDK is some 300-500 megabytes if I remember correctly (I may be wrong, but I think so). Wouldn't want to d/l that via 56k... (gulp)
You can try if you get along with MinGW (it is definitively smaller than the MS stuff), there are dependencies and patches for MinGW on the OGRE Sourceforge page, so it appears that it is possible somehow.
If you decide to use MinGW, there is a list of what to download on the Code::Blocks WiKi, or alternatively, you can just use the all-in-one-with-compiler package.
Note, though, that very likely Code::Blocks RC2 will be out on Monday (or during the next week), so before downloading anything on a slow link, you may want to consider waiting 2-3 days maybe.