Most condensers need phantom power. This will come from w\either the mixer mic input of you can use an inline Power supply between the microphone and the mixer if the mixer does not have phantom power.
Condensers although are not always better than dynamics as a general statement. Usually condensers will have a wider frequency response but they are also more sensitive than dynamics and therefore tend to pick up more around then over dynamics. They can sometimes therefore be more prone to feedback.
Condensers also overload (Distort) easier than dynamics at high SPL levels and are easily damaged if dropped.
Look up a very useful information on microphone usage for live performance at Shure.
http://www.shure.com/ProAudio/Resources/us_resources_performance
Hope it helps....
