How can I buy Mastercoins? What is currently the best way to purchase Mastercoins?

Are there exchanges out yet? 

Do I need some special Mastercoin-Address/Wallet?
The best way for you to purchase the funds are to go to http://www.buymastercoin.com/ and make  a purchase as described on the site. 

Or just go to the google spreadsheet that is used as a sort of an exchange where you can purchase from the MSC holders themselves: https://docs.google.com/spreadsheet/ccc?key=0ApGPLGUd5ZCzdHFxbnhHQjBDSDVKamY5UHlWdkNMNWc&amp;usp=sharing#gid=0

No need for a special Wallet but it is definitely recommendable to make a new address for the Mastercoins