Sorry, still a plain text page here =)
The API itself is still working the way it did before, you just have a few more options now.
This will still return a single value array containing a single player in a json formatted fashion.
New extra options are output format (xml/json). Default if not specified is json.
Plus the limit has been increased to 100 players per call.
http://api.sc2sigs.com/player/[output format]/[battle.net id],[battle.net id],[battle.net id]