Looks like the Lightweight USB Framework for AVRs (LUFA) has just been ported for ARM microcontrollers. NXP recently released a package for their LPC Cortex M3 family of ARM controllers. You won’t find a reference to LUFA on their nxpUSBlib description page (which we think is kind of sad), but if you grab a copy of the beta code the Version.h header file shows that it is indeed a port of the project. This is further backed up by the LUFA creator, [Dean Camera], who consulted with the NXP team doing the work.
The package provides an open-source USB stack that you can use in your projects as a USB host or USB device. We’re advocates of open source packages like this one as it makes it much easier for hobbyists to get help using the tools, and it allows the community to give back through bug fixes and feature additions.