[ejking]

UPDATE
The following tutorial has become outdated due to the release of Poof & BossPrefs (Both programs will hide icons - you only need one of them) (from Installer Source "BigBoss's Apps and Things" - Add Source http://sleepers/iphonerepo ) making it much easier and more automated.
However, if you prefer to hide your icons manually, the following will work.

Original Tutorial
Please Digg this if you find this tutorial useful.

This is a quick tutorial to hide icons in SpringBoard under version 1.1.3

In short, inside of the Application folder of the app you want to hide (i.e. for customize.app -> /Applications/Customize.app/) use plutil to convert the Info.plist into xml (from Eric's Utilities) [i.e. /Applications/Customize.app/Info.plist] and add the following code at the end of the Info.plist file (but before the </dict>) then restart Springboard (or the iphone, whichever u prefer)

<key>SBAppTags</key>
<array>
<string>hidden</string>
</array>

As a side-note, the iPhone understands both XML and Binary PLISTs all the same, so there is no need to convert the plist back to binary afterwards.

Here's a more extended tutorial:
For this tutorial, i will use an SSH client as i prefer modding my iPhone from a desktop, but you can use the terminal app within the iPhone just as well. (Thus, steps 1 and 2 are optional)
Side-Note: you do not need to deal with plutil at all (aka you can skip steps 3, 5-6) if you are dealing with 3rd Party Software... Original Apple Applications (such as the Calendar app) will need plutil conversion to be edited, however.

1. Install OpenSSH through installer on the iphone (if you haven't done so already)

2. Download an SSH Client on your computer (i recommend WinSCP if you are using windows - Its free).

3. Install "Erica's Utilities" through Installer

4. SSH into your iphone

5. copy "plutil" from "/var/root/bin" to "/bin" and give it Execute permissions (Octal Code 0755 in the Properties of plutil in the SSH Client)

6. Navigate to the app in "/Applications" that you want to hide and run command "plutil -c xml1 Info.plist" (This will convert it from binary to xml so you can edit it)

For Example: If you want to hide the Customize.app, do the following in the dir "/Applications/Customize.app/"

plutil -c xml1 Info.plist

7. Open up Info.plist for editing (in WinSCP simply double-click it)

8. At the end of the file (just before "</dict>") add the code from the top of this post.

9. Restart the iphone (or just springboard if you can)

10. VOILA! It's Hidden! To Un-Hide it, simply take the code out of the Info.plist file inside of the APPLICATION.app directory and restart again