Winterboard, the theming tweak on Cydia, is highly popular amongst iPhone users. With iOS 6, things are a bit tough because it's not yet completely compatible and users are running into issues with themes.
Almost all the themes available on Winterboard are compatible with iOS 5.1.1 or lesser. So far, I haven't seen a theme designed for iOS 6. So naturally, if you're going to look for themes right within Cydia, you can't get them installed and successfully running on Winterboard.
But there are other ways you can do it. For instance, by way of direct download.
Several theme designers put up their themes for download on the web instead of Cydia. You won't find many of these themes within Cydia and you'll have to manually install them.
That's where tweaks like iFile, software like iFunbox become handy.
We'll take a look at how you can install Winterboard themes directly without Cydia using a tool called DiskAid.
Note: DiskAid has been updated to support iOS 6.
How to install Winterboard themes without Cydia:
Step 1: Download and install DiskAid
Step 2: Download the theme file to your hard disk
Step 3: Open DiskAid, connect your iPhone
Step 4: Now, on the bottom-left of the software, choose Root Folder from the drop-down.
Step 5: Click on OK to continue
Step 6: In the folder pane, navigate to “Library” and then open “Themes”
Step 7: From the toolbar on top, click on “Copy Folder to Device” and select the theme folder that you downloaded from the web.
Step 8: That's it. Disconnect the iPhone and test the theme in Winterboard.
Alternatively, if you've got iFile installed, you can use it to copy files from your PC/Mac too. iFile sells for $4.00 on Cydia and comes with a ton of features. In my view, for most purposes, softwares like i-Funbox and DiskAid are quite sufficient. And these are free.