~snip
There are three main categories of bitcoin stakeholder. Someone may fall under more than one of these categories, and each category has its own legal considerations.
What are those categories, OP? Anyways, going to your subject, "Is Bitcoin Legal?" Yes, it is. And I think it depends on where you are or where you live, and what you wish to do with it. Currently, there are around 70 countries and territories in the world where the status of Bitcoin is legal, although it's not regarded as currency.
http://en.wikipedia.org/wiki/Legality_of_bitcoin_by_country