There is a useful list of accommodation choices provided here at the ROE website, and a longer list at the Edinburgh Guide. The University also offers some nice accommodation.

Here is a map marking conference locations and some convenient hotels.

If you want somewhere cheap, try the Ibis or Smiths.

If you want somewhere very close to the University, try Hotel Du Vin or Ten Hill Place.

If you want somewhere a bit snazzier, try the Apex City (or the nearby Apex International.