Tile collision information is available. You can get a collision layer (instance of TKObjectLayer) from a TKTileset using the tile's local GID:
TKObjectLayer* collisionLayer = [tileset collisionLayerForLocalTile:123];
This object layer contains all the TKObject instances (rectangles, polygons, polylines, ellipses) that you created in the tile collision editor. TKObject then gives you access to the points as vertices or CGPath for use in a physics engine.
You can also get a tile's vertices from TKTileLayer if you need to convert the tile itself to a physics shape.
The coordinates of these vertices/paths are relative to the object's position respectively tile's position. You may have to call TKTileLayer's convertToPoint: with the tile's grid coordinate and add that to the points if you need the path/vertices relative to the map node's position (aka absolute position within the map).