if you're willing to go past asm and use a high level lang, then usb can be your friend
easyhid is an awesome plug-in for proton basic, it lets you interface with a PIC uc not as a serial device but on an event level... HID = human interface device. coolest thing about hid are the drivers are pretty much universal, mac, linux, windows 98 and beyond, no disk required ... unlike serial emulation which most likely requires a driver
of course, serial device emulation is an option, and the high level lang all have plug-ins to help you generate code.