Arthur,
This is on our wish-list. I've actually already built the VOR, Vortac, etc images that can be dropped on the vector map. Just have to get it approved and work it into the Dev Schedule now. I'm even working on a Compass Rose to be enable or disabled around those VORs, etc.
Additionally, I've proposed a revised NRST list to show thinks like Airports, Navaids, Heliports, etc with frequencies.
I'm hoping you'll see these hit the iFly soon.