Marius
I looked at the sites you have mentioned here.
You are correct. It should be 'experience in'. For me to write 'experience in' sounds natural.
I just looked at my Longman Dictionary of Contemporary English.
It says 'knowledge or skill gained while doing a job is uncountable and the preposition is 'in'.
Mine is very old. Printed in 1995.
You have some experience in teaching, computing, etc.
I read the following last week.
You should have experience of teaching English for ...
This was written by a native English speaker.
I just checked with online dictionaries too. If you look at the on line Cambridge dictionary, it uses the preposition 'of' . On line dictionaries use the latest or rather state of the art stuff.
I reckon on line dictionaries are better than my old paper dictionries. On line Webster and MSN dictionaries don't provide details.
These things are confusing.
http://dictionary.cambridge.org/define.asp?key=27061&dict=CALD