is there a google calendar, yahoo calendar, msn calendar .. app for iPhone ?

Hi

My iPhone calendar is tied to my work (work mail + calendar)

Now my company is asking me to keep my calendar open to other colleagues / other employees in the company . I think I have to agree (not much choice in my personal situation ) ; I do not know how this will be done technically (probably they will synch ?? ..I don't know) but I need a personal calendar

I need a personal calendar where I can make some personal entries without everyone else in my company knowing

any good apps out there ?

free apps preferred. IF not, apps costing Max $5 ?


thanks in advance for your suggestions