good dictionary which support text to speech or real voice pronunciation?
OSX has a built in speech synthesizer which is quite good if you're looking for English pronunciation.

You can open up the terminal and enter the following command:

say "Hello! How are you?"


For dictionary I use the Dictionary application which is shipped with your OS as well. You can import multiple dictionary files into it. Here is a tutorial to do that.

The best part is that you can type ⌘ + ctrl + d to bring up the inline dictionary in cocoa applications. It's really handy.