I had USB comms in the "too hard" pile for a long time - it was only when Graham published his iHID: digital-diy.com/.../... program (with explanation) on the forum that I decided to take the plunge. That, and Jon's top tip: digital-diy.com/.../... about a cap on the Vusb pin made it all make sense! The Swordfish USBHID library takes care of the heavy-lifting on the PIC side.
Happy to share the source for my PC app but to be honest it's just a different front-end to Graham's iHID code - let me know if you want to see it though.
Perhaps there's scope for an article demonstrating a "hello world" type application using USB comms between a PIC and a PC?
I'm floored by how good this looks, from the inside-out. From the well thought out design, real subtle mix of technology with old materials, and it even has a USB port! You should consider using this as a prototype for mass-production!
One could even put 8-segement displays behind the front to display different data (not just Hours (h) and Minutes (m), but possibly bandwidth usage, email notifications, etc.