Speed skating blades are quite different than those used for hockey and figure skating. Not only are they longer but they are also flat ground. If speed skates are sharpened using a machine designed for hockey or figure skates, it will permanently damage the blades.
Please click the link below for a video demonstration of sharpening skates:
Here is a good discussion paper on speed skate sharpening.
To properly maintain blades:
Be sure to fully dry the blades after each use to prevent rust from developing. Store the blades in a cotton/fleece skate cover between practices. Use a hard plastic skate guard when going on and off the ice.
Have the rocker and bend on skates checked at least twice (beginning and mid-season) per season by a club coach or equipment person.