iCal duplicates on syncing with iPhone

[Ultra Violent]

Each time I sync my iPhone with my iMac it duplicates events on my Macs iCal, how do you stop that?

And how the hell do you accept an iCal invite sent by mail on your iPhone?

[PJ S]

Accepting invite is as easy as click on the link/attachment in the email received, but need to turn on invite alerts in Settings, under Mail, Contacts, etc.

As for the duplication, if your iCal on the Mac is all up to date, the next time you sync the phone, scroll down and tick the option to replace info on the phone with iCal data.
That should untwist its knickers for you.