This and "Freut sie sich auf?" were puzzling me -- how do I know it's "looking forward to?" Browsing in Langenscheidt, I happened to notice that it's the preposition, "auf": "sich auf jdn/etw freuen = to look forward to seeing sb/ to st"
Lots more here -- notice the prepositions in particular: http://www.dict.cc/?s=freuen
Good question. I tried that and it gave me a popover hint saying "Are you happy about that? = Freut ihr euch darüber?" However, when I hover over "freut" the first translation is "happy"...
Although Duo's accepted answer matches what I learned from Pimsleur, the hints are very inconsistent.
I hope this will help a bit: http://yourdailygerman.wordpress.com/2012/06/19/da-words-meaning-german/
You don't say "happy for it" in English. You can be "happy about something (e.g. an event)". You can be "happy with something (e.g. a situation)". You can be happy "for someone" however, indicating you are pleased by someone else's good fortune. I don't know that there is a grammatical reason for that. It is just the way it's said.