Swanman,

John already has a VoiceLive. As I stated earlier that thing is a complete vocal processor, including a pre-amp. It also can provide phantom power.

A microphone pre-amp amplifies the low signal coming from a microphone and brings it up to a more usable level signal. Computer soundcards most often are not made to record music with, hence they're not equiped with a mic pre-amp. Most interfaces (like a Tascam US122L) on the other hand are designed to record and to work with DAWs and do have (a) mic-preamp(s) on board.

Active microphones, like condesor mics, need a certain electrical power to operate. Phantom power is a method where an electrical DC voltage is sent via the microphone cable to provide this power for the microphone.