Firstly, thank you so much for all your replies..
Peyman1987: Thank you for your advice and especially the phone number for the ILI. I will give them a ring. I’m sure Tehran isn’t too bad for living in, there are over 7 million people living there after all!
Love-to-learn: Thanks for the link to Kish. I’m surprised and happy to learn that there are British teachers already teaching there. Maybe it won’t be impossible for me to get a work-visa in that case! I will try and contact them about exams, interviews etc. My problem is that in order to get a work-visa, I need a letter of confirmation from the company I will be working at (according to the Iranian embassy website). But if may prove difficult to get this before the interview. I will try and explain it to them.
@mir: Thanks for your suggestion. I have never worked in media but it would be interesting to start in Iran! I think I would probably have to work at making my appearance satisfactory though!
Once again thanks for all your help everyone. You have also worried me a little too however. The level of everyone’s English here is so good, I’m not sure that you will need me in Iran!