Chiming in with one of my releases, as somebody suggested I do I'm sure you've all heard of my previous Folders application that was well featured, though perhaps not too user friendly. Well, here's a post about the on-device branch of the application
The boring details are on my site, but since this is XDA, I'll go a little in depth. The application allows folder entries to be created, which can then be pinned to the start menu. To add applications to them, since I don't have interop access (if someone wants to give me a link on how to use the file system on Samsung 1st gens, I'd love to take a look at it. Can't find anything after Mango), the application searches the Marketplace and pulls down the proper GUID and application image. Built-in system applications can also be added, which are hard coded. If you want to be creative, you can enter your own GUID, but it won't have a custom image. Of course, this is all subject to change if I can get some ideas on how to smooth out the user experience, but it's a work in progress
So far, it looks like this:
-Allows adding Marketplace and System applications into folders, which are then pinned to the start screen
-Now pin websites into the folders, too!
-Regional Marketplace support (en-US, en-GB, fr-FR, etc)
-Completely on device
-Requires only developer unlock, no interop required!
-Custom tiles implementation
-Perhaps interop support for people with interop unlock
Known bugs (be sure to report 'em )
-Exiting the add app popup is hard
-Doesn't support light theme too well (not a lot I can do there, unless I branched it)
-Some people report COM issues; report if you have this problem. Also, try reinstalling it, that seems to help.
And you can download it at the bottom of this page: http://windowsphonehacker.com/folders
Cheers, let me know some feedback!