How many people are in the band? If it is just one guitar, one vocal, bass, and drums, the I would dedicate a track to each of them (you would have to sub-group the drums).
If your band is more than that, I would place two mics in the room to pick up the live PA sound and stage volume; seperate them for stereo. If your PA is set up for stereo, I would use the other two tracks to capture the stereo main mix off the PA board, or if it is mono, then just use one track from the main mix of the PA board.
In either case, play a song through your setup and play it back and make adjustments to your stereo mics. Rpeate until you zare satisfied with what goes to tape then record the rest of your songs.