The parallel port conforms to TTL logic levels. About the current, I am not sure what you exactly mean. If it means driving something like an LED from the parallel port, I would recommend using a buffer like 74LS244 or 74LS541 (if u want 8-bit bus-like output). You CAN drive an LED directly though, but incase your series resistor fails, it might do some damage to the port which is irraparble.

Regards
Aman