Both Proton and Swordfish use a USB dongle. One computer per licence.
edit: I agree with picbits, I use assembler and I find I try to think much the way the PIC does.
BASIC, C, Forth, JAL are all abstracts and are the developers view on the processor. You still need an in depth knowledge of the processor or you'll never figure out why your program doesn't work. Some languages will make assumptions, some won't.
The BASIC Stamps are popular because they are such simple devices on very ancient PICs (16C57) and make plenty of assumptions.
If you must use BASIC or C for that matter use C18 or Swordfish BASIC and avoid all 12bit and 14bit core PICs and use just the 18F series PICs.
Just my 2cents.