I need 30 min timer circuit using PIC

Hello,

I need a circuit with the following characteristics:

- when a pushbutton is pressed a led will be on for exact 30min then it will be off
- if pushbutton is pressed when led is on, then the time(30 min) will start again.

I have not done anyting with PIC yet. But i think i can do it. Can anyone give me some information about how to do this circuit? Which pic i should use?

Thanks