Changing icons in Snow Leapard

What's the problem? Details might elicit a cogent response.

You have to go into the Resource and replace the .icns file. I've done this successfully with Safari and Mail. For example Mail > Contents > Resources > app.icns

Message was edited by: TreStange

Thanks for clarifying. See http://www.macosxhints.com/article.php?story=20090901205400914 for a possible solution.

CONTROL-click on Mail.app icon in /Applications/ and select Show Package Contents. That opens up the folder masquerading as a single package file. Drill down to the Resources subfolder and replace the icns file. The Terminal command is incomplete, but not required, since CONTROL-click and hold on the Finder's Dock icon reveals a Relaunch option.

baltwo, that will work for changing icons but not color labels which is what the OP wants to do. Unfortunately, there are no graceful workarounds.
Here are a few possible ways to do it, all requiring terminal.

Method 1. do what that mac os x hint suggests.
quit Finder from Activity Monitor. it will stay quit and not restart buy itself that way. then start Finder as root by running the following terminal command

sudo /System/Library/CoreServices/Finder.app/Contents/MacOS/Finder 

this will start finder as root and you'll be able to change labels (and if you want icons) normally.

then quit Finder from Activity Monitor and start it again normally by clicking on the finder icon in the dock.

Method 2.
activate root account, log in as root and do it from there the usual way.
log out and log back to your account and deactivate root.

method 3. Change ACLs on /Applications temporarily.

First run

sudo chmod -R +a "admin allow list,addfile,search,delete,add_subdirectory,deletechild,readattr,writeattr,readextattr,writeextattr,readsecurity,writesecurity,chown" /Applications/*

then change labels and/or icons as you like normally. then put the ACLs back how they should be.

sudo chmod -RN /Applications/*
sudo chmod +a "everyone deny delete" /Applications/Utilities

Sorry, missed the part about starting the Finder as root; however, I was also letting the OP know how to get to the icns file.

arseymcflipflop wrote:
In fact, ignore my last post, I think VK's 'method 1' looks like my best option but again, could someone put it in layman's terms for me please? Much obliged.

I thought it was kind of in layman's terms already 🙂 here it is again with some more details.

Open terminal.app and Activity Monitor.app. Both are located in /Applications/Utilities. Activity monitor will show the list of your active processes. select Finder and use the Quit button in the toolbar to quit it.
then paste the following into terminal window

sudo /System/Library/CoreServices/Finder.app/Contents/MacOS/Finder 

press enter in terminal. you'll have to enter your admin password (which you won't see). that's normal. this will start finder but as root not you so you'll have read+write access to everything from this finder.
Change any icons you want in the usual way. then log out/in.