ErgDB has opened up a basic API to search and export workouts. Right now, workouts can only be exported in .erg format, but Multi-Rider and PowerAgent will be added soon. Below are sample calls.
http://www.73summits.com/ergdb/api/list/json (result is JSON)
http://www.73summits.com/ergdb/api/list/csv (result is CSV - default)

The default format is CSV	   
id,workoutType,author,name,workoutTime,dateAdded (header/fields)
This will return all workouts with the following parameters above. You will use the id to generate workouts
http://www.73summits.com/ergdb/api/workout/16/220/erg (result is erg file - default)
http://www.73summits.com/ergdb/api/workout/16/220/poweragent (result is poweragent)
http://www.73summits.com/ergdb/api/workout/16/220/mrc (result is multirider if available)
	- id is the workout id
	- ftp is the persons ftp
	- format is optional and the format of the file
This will return the raw .erg contents of a workout. The $id and $ftp parameters are required.