"sorry to" と "sorry for"

"to" は今、"for"は過去に起こっていることに対して

Sorry to keep you all waiting. 

みなさんお待たせしております（お待たせがこれからも続く：まだお待ちください）

   To be sorry to + infinitive = to apologize for a present action

   I will let you wait after I say this

Sorry for keeping you all waiting.  

みなさんお待たせしてすいません（これ以上待たせない：では始めましょう)

   To be sorry for + verb with -ing = to apologize for a past/earlier action

   I let you wait before I say this

I'm sorry to hear that. (今聞いて）お気の毒に

I'm sorry to interrupt but could you come with me for a second?

I'm sorry for lying to you, I won't do it again.