Description for all the moves
Water Pledge
Water Pledge deals damage at base power 80. If a teammate uses Grass
Pledge or Fire Pledge in the same turn, the moves combine into one
attack of base power 160 and added effects appear.
The faster Pokemon moves first but waits for the other Pokemon to make
their move. When the slower Pledge user moves, the combo attack hits
the Pokemon the slower user was targeting.
If Water Pledge is used with Grass Pledge, the move animation shows
Grass Pledge and a swamp envelops the foe's team that halves the
opponents' speed for 4 turns.
If Water Pledge is used with Fire Pledge, the move animation shows
Water Pledge and a rainbow appears in the sky on your team's side that
doubles the chance of moves' secondary effects occurring for 4 turns.
Fire Pledge
Fire Pledge deals damage at base power 80. If a teammate uses Grass
Pledge or Water Pledge in the same turn, the moves combine into one
attack of base power 160 and added effects appear.
The faster Pokemon moves first but waits for the other Pokemon to make
their move. When the slower Pledge user moves, the combo attack hits
the Pokemon the slower user was targeting.
If Fire Pledge is used with Grass Pledge, the move animation shows
Fire Pledge and a sea of fire envelops the foe's team is created that
damages opponents 1⁄8 of their maximum HP each turn, for 4 turns.
If Fire Pledge is used with Water Pledge, the move animation shows
Water Pledge and a rainbow appears in the sky on your team's side that
doubles the chance of moves' secondary effects occurring for 4 turns.
Grass Pledge
Grass Pledge deals damage at base power 80. If a teammate uses Fire
Pledge or Water Pledge in the same turn, the moves combine into one
attack of base power 160 and added effects appear.
The faster Pokemon moves first but waits for the other Pokemon to make
their move. When the slower Pledge user moves, the combo attack hits
the Pokemon the slower user was targeting.
If Grass Pledge is used with Fire Pledge, the move animation shows
Fire Pledge and a sea of fire envelops the foe's team is created that
damages opponents 1⁄8 of their maximum HP each turn, for 4 turns.
If Grass Pledge is used with Water Pledge, the move animation shows
Grass Pledge and a swamp envelops the foe's team that halves the
opponents' speed for 4 turns.
I feel they are worth it. If I'm not wrong, even the elemental monkeys can learn the Pledges.
Source: http://pokemondb.net/move
Hope I helped,
gau222 ;) .