Paul over at Modaco has just made available a really useful application called CallHistory2Calendar which does exactly what it says (on the tin) by publishing your call history into your calendar.
Particularly useful for those who need to keep track of their calls, perhaps for charging back to an employer, CallHistory2Calendar takes your call history, and each time it changes (i.e. after a call), it inserts it into your calendar as entries in appropriate categories (Calls: All, Calls: Incoming, Calls: Outgoing, Calls: Missed).
To get hold of it you need to be a Modaco Plus member (which costs 35 pounds a year) however there are a whole bunch of other benefits and applications too....
You can get more details on the application and how to sign up for Modaco Plus HERE