how can I format cells as Minutes:Seconds:Milliseconds?

Hi all,

I have two questions. I need quick reply please.

1) I want to add data of type: Minutes:Seconds:Milliseconds.
2) I wanna make a chart showing the user number and his time.
It is about users completing task at different times (these times are recorded in Minutes:Seconds:Milliseconds). this chart is required to show me who is the user who took the largest time, and who is next and so on.

I use excel 2007

Thanks for caring and reading my message.
waiting your reply