Watch the Beyond 21: More Charts online guitar lesson by Ravi from Learn Guitar in 21 Days
Reading barre chord charts is the same as open chord charts, except that you should always check for a Roman numeral next to the first fret shown in that chart.
If there is one, then that first fret is not actually the 1st fret, but rather, the fret indicated by the Roman numeral (i.e. "V" = 5th fret, and the frets below will be the 6th, 7th, 8th, etc.). Keep in mind that barre chords are played all over the neck so the fret indicated is where you lay the "barre" down.
Watch the video for a demonstration and examples.