How to customize Finder sidebar icons I'm using Dropbox and replacing some of the standard user folders like Documents and Pictures with symlinks to locations in my Dropbox. I can easily set the icons of these symlinks to match the icons of the standard Documents and Pictures folders, but I can't find a way to also change the symlinks' appearance on the Finder sidebar to look like the native Documents and Pictures folders.

In short, I've placed custom folders in the Finder sidebar; is there a way to change the icons they're given?

I've looked into Candybar, but it seems like that's mostly for changing the appearance of all appearances of the standard icons, whereas I just want to make a plain and ordinary folder look like a standard user folder.
I believe this worked in Snow Leopard, and is broken in Lion (perhaps on purpose). You won't be able to set your own icons for just any folder — file a bug if you'd like to see this fixed. But as you noted, they can be changed for the standard icons, using CandyBar
You can also just edit the image files themselves, at /System/Library/CoreServices/CoreTypes.bundle/Contents/Resources. The icons are named Sidebar___.icns.