When a card can use several abilities at a given moment, you've seen that a menu pops up.
For example, birds of paradise will offer you to add 1 green mana, or 1 white mana, etc...
The text of a given ability is displayed through the method "getMenuText()" in any MTGAbility class.
See for example the class ADrawer:
http://code.google.com/p/wagic/source/b ... ties.h#138
Of course, sometimes it's a bit more complicated, for example the one for mana producers:
http://code.google.com/p/wagic/source/b ... y.cpp#2271
if this method is not overriden, the one from the parent will be used. The most generic one is defined in ActionElement, and says "ability"
http://code.google.com/p/wagic/source/b ... ement.h#48
Ideally, most of these should be overriden to give the player the most precise explanation of what he is going to do. This is not always easy