I've heard a few things about green tea... The asian community swear that drinking a cup of green tea after a meal help with digestion, breaking down fats and "flush" them quickly. It is also a great source for anti-oxidents. As far as the supplements go, like "Mega T", most of the studies show that the caffeine content is the main fat burning property, but there is not a ton of data supporting it's effectiveness.
In my unprofessional opinion, fresh brewed green tea (with or without caffeine) would be the way I would go... The pills seem like a waste of time and potentially dangerous if you have a sensitivity to caffeine.
I WILL wear an itsy bitsy teeny weeny yellow polka dot bikini....