hmm not on me. actually, i doubt there are many resources about medium and meaning but try googling it.
just off the top of my head though...
consider various media and their target audiences or expected audiences - the internet/flash websites for the youth, television shows at certain time slots for certain demographics, radio for those on the move, etc.
then consider elements of media which can affect meaning - for example, imagery through pictures or through words, sound or no sound, appearance, elements etc. things like headings can cater for different demographics - consider the shock value of some trashy magazine aimed at housewives compared to the informative headlines in the AFR for example.
The way language is used often influences meaning - it's no use writing a tech article in slang, or writing a colloquial article using only high-tech industry buzzwords. They're catering for different markets and have different purposes.
Umm... yeah, I'm too tired to think of anything else. Hope it helps.