LibUsbDotNet Linux support is available as of version 2.2.0! See the Using LibUsbDotNet with Linux walk-through at http://libusbdotnet.sourceforge.net/V2/html/0c99e44e-ac77-4177-805a-5c9366b5253f.htm
Future versions of LibUsbDotNet will support both Linux and Windows operating systems. It will require the Mono 2.0 runtime and libusb 1.0.x usb driver. This new version of LibUsbDotNet is scheduled for release on Dec. 15. 2009.
PicDotNetTools is a a combination of firmware, utilities and applications
for PIC USB developers, Currently, utilities and applications are
specific for 18F series USB micro-controllers.
PicBootDotNet (MCHPUSB Bootloader in C#)
PicBootDotNet is an alternative to Microchips PdfsUsb application. It
works with the same device firmware (MCHPUSB), only using LibUsbDotNet
(LibUsb or WinUsb) for its device driver instead of the generic mchpusb
driver.... read more