The Linux kernel, assuming you have compiled in or loaded the lp
device (the output of cat /proc/devices should include the
device lp), provides one or more of /dev/lp0,
/dev/lp1, and /dev/lp2. These are NOT assigned
dynamically, rather, each corresponds to a specific hardware I/O
address. This means that your first printer may be lp0 or
lp1 depending on your hardware. Try both ;)
One cannot run the plip and lp drivers at the same time. (Is this true port-by-port, or globally on a machine? I think globally, but I haven't tried.)
There is a little utility called tunelp floating about with which
you, as root, can tune the Linux lp device's interrupt usage, polling
rate, and other options.