I depend heavily on ManicTime for capturing billable time but for phone calls I often end up missing some billable hours.

I'm very fond of both products/companies so integration between ManicTime and a mobile operator like Ting might be a nice marketing boost to both companies. Further, Ting already has Android and IPhone apps you could piggy-back on. I've sent this suggestion to them as well with a pointer to ManicTime web site.

Such an app could be as simple as a prompt for the call's purpose after calls. A phone number catch/ignore list would minimize annoyance factor. Input via voice OR pick-list would make it usable while driving. Voice recognition is now at a place where it could work nicely for this.

To get the data into ManicTime it could be as simple as importing a CSV list but the ability to sync the data through Bluetooth or USB connection would be icing on the cake.