It's not quite that easy... The XYRS is a centroid file, also called x/y file, pick-n-place file... Each assembly house has different requirements for micro assembly and what they would like you to furnish. Eagle, Altuim, etc. will generate centroid files... Microfab requires XYRS files and has EDA libraries for Eagle, Altuim, Diptrace, and KiCad. Component manufactures also furnish libraries for these EDAs that comply to standard orientation. Fritzing parts are furnished by everyone and may not conform... they could be 90, 180, or 270 deg. out. The actual datum XY, rotation references, No.1 pin location, and package footprint may not be available to conform with the micro assembly requirements or standards... The XY location in Fritzing may not be the datum based on a pad stack.
With all that said, you can still use Fritzing to generate your centroid file by using products such as Fab 3000, GraphiCode, Unisoft, Cam350, or Mentor Graphics with Fritzing's gerber data...
You may also want to look into http://www.compuphase.com/visualplace/visualplace_en.htm , free software writer by a Dutch programmer...