Just wanted to chime in here:
We applied to iranianvisa.com back in May-ish, hoping to go to Iran in August.
Long story short, they procrastinated and failed to communicate, and asked us to re-send things... when we finally approached Tourin Zamin in July to start a new application, they informed us that independent travel in Iran is currently impossible for citizens of the UK, USA, Canada. See http://www.tripadvisor.co.uk/ShowTopic-g293998-i9139-k7232531-No_More_Independent_Iran_Travel_for_British_Canadians-Iran.html
for more confirmation (since Feb 2014).
Iranianvisa.com were happy to take our money and are still emailing us requesting we re-send passport images etc. No chance of a refund.
Have to conclude that they are running a scam (even if they also do legitimate business).