If your Pro668 is still "stock" you might find that performance on P25 digital is not all that it could be. So, before you get too involved, you might consider sending it to Whistler to be updated to the latest firmware/DSP. It will add features and more importantly, much better DSP which will greatly improve digital decoding quality.
Everything about a stock 668 is frustrating,
Update it then update to ezscan for the ws1080 and you will find it easier to use and program and performs much better thanks to all the fixes whistler has done to the firmwares and to ezscan. The it truly can be programed via zip code with the option to pick and choose what you want from the library.
Scannermaster is the only one that comes immediately to mind. They don't work for free or particularly cheaply, and there have been mixed reviews but I believe that they'll program it for you. Do you already own the scanner? | Scanner Master
But you will be better off if you just go back, study the app and read the available material about it (there's a ton of help right here on RR), and learn to use it yourself. I've said it before, if an old fart like me can figure it out, it can't be too difficult.