I am aware of the great, wide new spectre of possibilities, but I have
almost no clue about Html5.

As one of the (from many) way to exponentially send back IE6 to the Big-Bang era - is to massively accept new technologies and methods... Well let's go with HTML5. How to embrace it in the meaning of compatibility without spending 70%+ time we usually spent looking at a Microsoft product. 

Let's say we decide to start our new project in HTML5, what are the best practicies, problematics, links, infos... all related with older browsers compatib.. 

Do we have to create html5 docs apart or are they handable and how by oldyes.

Any good link or suggestion or explanation?