Alright until summerboard and customize come out this guide will help you get custom themes. You can only change icons for original iphone apps: ie calculator, safari, ipod, ect. You can change the dock and a few other images.
Icons:
1. Navigate to /Applications
2. Open the folder of the app you wish to change the icon of.
3. Find icon.png. Rename it to icon.png.bak
4. Place your downloaded icon into that folder. It must be named icon.png
5. Respring and enjoy
6. Repeat this process for the icons you want to change for each apps
Dock:
1. Navigate to /System/Library/CoreServices/SpringBoard.app
2. Find: SBDockBG
3. Rename it to SBDockBG.png.bak
4. Place your custom icon in and have it named: SBDockBG
Carrier Image:
1. Navigate to: /System/Library/Carrier Bundles/ATT_US.bundle
2. Rename: Default_CARRIER_ATT to Default_CARRIER_ATT.png.bak
3. Place the custom image in and have it named: Default_CARRIER_ATT
4. Rename: FSO_CARRIER_ATT to FSO_CARRIER_ATT.png.bak
5. Place the same custom image in but have it renamed: FSO_CARRIER_ATT
Sim Badge Notification:
1.Navigate to /System/Library/CoreServices/SpringBoard.app
2. Find SBBadgeBG and rename it to : SBBadgeBG.png.bak
3. Place your custom badge image in and have it named: SBBadgeBG
Sim Bubble:
1. Navigate to /Applications/MobileSMS
2. Repeat the same steps for Balloon_1(You) or for Balloon_2(receiver)
Icons:
1. Navigate to /Applications
2. Open the folder of the app you wish to change the icon of.
3. Find icon.png. Rename it to icon.png.bak
4. Place your downloaded icon into that folder. It must be named icon.png
5. Respring and enjoy
6. Repeat this process for the icons you want to change for each apps
Dock:
1. Navigate to /System/Library/CoreServices/SpringBoard.app
2. Find: SBDockBG
3. Rename it to SBDockBG.png.bak
4. Place your custom icon in and have it named: SBDockBG
Carrier Image:
1. Navigate to: /System/Library/Carrier Bundles/ATT_US.bundle
2. Rename: Default_CARRIER_ATT to Default_CARRIER_ATT.png.bak
3. Place the custom image in and have it named: Default_CARRIER_ATT
4. Rename: FSO_CARRIER_ATT to FSO_CARRIER_ATT.png.bak
5. Place the same custom image in but have it renamed: FSO_CARRIER_ATT
Sim Badge Notification:
1.Navigate to /System/Library/CoreServices/SpringBoard.app
2. Find SBBadgeBG and rename it to : SBBadgeBG.png.bak
3. Place your custom badge image in and have it named: SBBadgeBG
Sim Bubble:
1. Navigate to /Applications/MobileSMS
2. Repeat the same steps for Balloon_1(You) or for Balloon_2(receiver)