Here you can find some detailed introductions to the new features in
Ant 1.6 (to try them download the released version from the Ant download site)
NewAntFeaturesInDetail/MacroDef - define new tasks as macros based on other tasks
NewAntFeaturesInDetail/PresetDef - define new tasks by providing default values for attributes or child elements of existing tasks
NewAntFeaturesInDetail/Import - import build files - and maybe even override targets in the imported files with targets of your own
NewAntFeaturesInDetail/NewIntrospectionRules - new naming conventions for methods have been added that make writing and using custom selectors, filters or conditions a lot easier.
NewAntFeaturesInDetail/DefaultExcludes - the list of default exclude patterns is no longer hard-coded but can be changed at runtime